Riftbound Frequently Asked Questions

Ruling: You draw the card when your Discipline resolves (as the chain resolves backwards), not when it is initially played onto the chain. Sequence: - All Disciplines are added to the chain first - The chain resolves backwards - Each Discipline resolves one at a time, granting +2 and drawing a card - After each Discipline resolves, there is a window to react with newly drawn cards Nuances: - You can draw a card from your Discipline resolving, then use that newly drawn card to react before the chain finishes - You cannot react to your own Discipline with the card you drew from it, but you can react after it resolves to earlier effects in the chain

Ruling: Dr. Mundo gains +2 might from the Stupefies before Yasuo's attack ability resolves, bringing him to 8 might and allowing him to survive. Sequence: - Both players pass priority and the chain begins resolving - First Stupefy resolves and goes to trash (Mundo now at 7 might) - Second Stupefy resolves and goes to trash (Mundo now at 8 might) - Yasuo's "When I attack" ability resolves, dealing damage based on his current might Nuances: - Spells enter the trash after they execute/resolve - Dr. Mundo's might passively increases as cards are put in the trash area - The chain resolves in reverse order, so spells resolve before triggered abilities that were placed on the chain earlier

Ruling: Cards go to the trash as part of the resolution of the card, which happens before cleanup. This means Mundo's passive will increase before checking if he dies from damage. When might modification effects like Convergent Mutation or Switcheroo are applied, they snapshot the might difference at the time they're played, then Mundo's passive increases by 1 after the spell resolves and goes to the trash. Sequence: - Spell effect applies (damage dealt or might modification snapshotted) - Spell card goes to trash as part of resolution - Mundo's passive recalculates with the new trash count - Cleanup checks occur (such as whether Mundo dies) Nuances: - Convergent Mutation only increases might, it cannot decrease - Might modifications from spells like Switcheroo snapshot the difference and apply it continuously for the turn - If trash cards are recycled or removed after a snapshotted might modification, Mundo's passive adjusts but the snapshotted modification remains unchanged - When multiple might modifications happen simultaneously, apply increases (+) first, then decreases (-)

Ruling: Combat cannot start until the chain is empty. Dragon's Rage's reflexive trigger must resolve before combat can begin, meaning units are not yet attackers or defenders when the reflexive trigger resolves. Therefore, Ahri Legend's trigger (which requires combat to have begun) does not reduce might before Dragon's Rage's reflexive trigger resolves, and shield/assault are not active during the second part of Dragon's Rage. Sequence: - Dragon's Rage is played, moving a unit onto a battlefield with another unit - Combat is staged but cannot start yet - Dragon's Rage's reflexive trigger goes on the chain - The reflexive trigger resolves (units may die here) - Only after the chain is empty can combat begin - Ahri Legend's trigger would occur when combat begins (if units still exist) Nuances: - Since units are not in combat when Dragon's Rage's reflexive trigger resolves, they are not attackers or defenders yet - Shield and assault keywords are not active during the reflexive trigger resolution

Ruling: Dragon's Rage does not trigger healing because it is not a combat. The unit moved by Dragon's Rage will not be healed after destroying the enemy unit. Nuances: - Dragon's Rage is a movement effect, not a combat action - Combat-related healing effects do not apply to Dragon's Rage interactions

Ruling: The draw is a trigger that goes on the chain when you choose the target (as you put the spell on the chain), and it will resolve after everything placed after it resolves, but before the spell itself resolves. Sequence: - You cast a spell targeting a friendly unit - The spell goes on the chain - Dreaming Tree's trigger goes on the chain at the same time - Items placed after the trigger resolve first - The draw trigger resolves - Finally, the original spell resolves

Ruling: You cannot ready your runes twice from a single Ekko dying with Karthus on the field because Ekko's "recycle me" is a mandatory cost paid at resolution, and you cannot recycle Ekko twice. However, if you have two Ekkos on the field, you can ready runes between each Deathknell trigger resolving. Sequence: - When Ekko dies, Deathknell triggers enter the chain - You can tap runes for energy in response before triggers resolve - When each Deathknell resolves, you must recycle that Ekko to ready your runes - You can tap runes again between resolution of different triggers Nuances: - The "recycle me to ready your runes" uses "[do X] to [do Y]" templating, making recycling a cost paid at resolution, not an upfront cost - This cost is mandatory (not "may"), so you must recycle Ekko and ready your runes when the trigger resolves - Karthus doubles the trigger, but the second instance still requires recycling the original Ekko, which is already recycled - With multiple Ekkos dying, each can be recycled separately for their own trigger

Ruling: Switcheroo fully resolves first (swapping the powers), then Embermonk's trigger goes on the chain and gives it +2 might. Sequence: - Switcheroo is played and must fully resolve - The power swap occurs - After Switcheroo has fully resolved, Embermonk's "when you play a spell" trigger can go on the chain - Embermonk gets +2 might Nuances: - "Play" in Riftbound means fully resolve - the spell must completely finish resolving before play triggers activate - If Switcheroo is countered (e.g., by Defy), Embermonk won't get the +2 at all since the spell didn't fully resolve

Ruling: The Sand Soldier token still plays to the battlefield because Emperor's Dais explicitly specifies to play it "here" (at the battlefield), which pre-selects a valid location regardless of whether you control the battlefield when the unit finalizes. However, returning your only unit causes you to lose control of the battlefield during cleanup, which triggers a showdown. Sequence: - Emperor's Dais Conquer ability goes on the chain - You pay 1 and return your only unit as the ability resolves - The Sand Soldier token is put pending on the chain and the ability finishes resolving - During cleanup after the ability resolves, you lose control of the battlefield (no units remaining) - The Sand Soldier token finalizes on the chain during this cleanup - The Sand Soldier plays to the battlefield at the location pre-selected by Dais's ability text - A showdown is triggered because you don't control the battlefield - You gain control of the battlefield again (but don't conquer again, as you can only conquer once per turn) Nuances: - The ability's text "play it here" pre-selects the battlefield as the valid location, so the token can still be played there even without control - Units use the chain like other cards but resolve immediately once finalized - There is a cleanup after the trigger resolves and before the unit finalizes, during which control is lost - You cannot conquer the same battlefield twice in one turn

Ruling: The opponent controls both triggers and can order them as they choose. Nuances: - Fading Memories only gives a unit the Temporary keyword - Like any other unit with the Temporary keyword, the trigger belongs to the unit's controller, not the player who gave it the keyword

Ruling: Falling Comet still deals 6 damage to Jinx even though she moved to a different battlefield. The spell was already targeting Jinx when cast, and as long as Jinx remains at a battlefield (any battlefield), the spell resolves normally. Sequence: - XiaPoo casts Falling Comet targeting Jinx at the attacked battlefield - Opponent cannot respond with Ride the Wind because actions cannot be played in response to other actions - only reactions can respond to actions - Falling Comet resolves, dealing 6 damage to Jinx - After Falling Comet fully resolves, focus automatically passes and the opponent could then play Ride the Wind Nuances: - If Jinx had been moved to the base (hand or deck) instead of another battlefield, Falling Comet would fizzle - If Jinx returned to hand and was replayed, she would become a new object and the spell would fizzle - You cannot respond to an action with another action; only reactions can be played while a chain is open - Focus automatically passes after an action resolves - you cannot follow up your own action with another action without giving your opponent an opportunity first

Ruling: You must pay the Deflect cost for each time the unit is targeted. Nuances: - The specific Deflect cost depends on the unit being targeted - If a unit is targeted twice by Falling Star, you pay the Deflect cost twice

Ruling: No, the unit does not exhaust. Only standard moves have an implicit exhaust cost. When a spell tells you to move, you only do what the spell says. Nuances: - Standard moves require units to exhaust themselves as a cost to move - When a card effect says "move," it provides free movement without requiring the unit to pay the exhaust cost

Ruling: When Zhonyas is played from hidden, it always gets recalled to base right after resolving. Nuances: - This applies regardless of whether you would lose control of the battlefield - The recall happens immediately after Zhonyas resolves

Ruling: Arcane Shift gets banished by its own text and is not recycled by Fizz. When Arcane Shift finishes resolving, it banishes itself as part of its resolution, and Fizz's delayed recycle ability cannot target it in the banishment zone. Sequence: - Fizz's WYPM effect plays Arcane Shift from trash - Arcane Shift resolves completely, including banishing itself as part of its resolution text - Fizz's delayed recycle ability attempts to trigger, but "that spell" is no longer a valid target in the banishment zone - Arcane Shift remains banished Nuances: - The recycle instruction from Fizz is a delayed ability that cannot define "that spell" once it has moved to the banishment zone - This is not a Golden Rule case because the target becomes invalid rather than the rules disallowing the action - Effects that reference cards in banishment only do so by means of also putting the cards there (Fizz didn't banish the spell)

Ruling: When Fizz targets a spell with Repeat, the player chooses whether to pay the Repeat cost, same as if playing the spell normally, but only pays the Repeat cost (not the original spell cost).

Ruling: When a spell played from trash using Fizz's ability is countered, it goes to trash rather than being recycled. Sequence: - Fizz's ability is used to play a spell from trash - Opponent counters the spell with Defy - The countered spell goes to trash Nuances: - Fizz requires the card to be played (not countered) in order to recycle it - Countered cards are not considered played for the purpose of Fizz's recycle effect

Ruling: Immortal Phoenix's triggered ability triggers immediately and is added to the chain after Flurry of Blades resolves. It does not wait for the next Open State. Sequence: - Flurry of Blades resolves - Phoenix triggered ability is put on chain - Any player can react to it - Phoenix triggered ability starts resolving - You can pay {1}{F} - If you paid, Phoenix itself is put on chain as pending item - Phoenix triggered ability ends resolving - Phoenix itself starts finalizing - Make all necessary choices (where to put it) - Phoenix finalized and resolves immediately (put at chosen location) Nuances: - All main deck cards and abilities start as pending items on the chain - The pending items concept delays making necessary choices and paying costs during resolution of another item - In most cases the pending concept doesn't need to be explicitly considered, though all chain items technically start as pending

Ruling: Karma only triggers once when Forge of the Future recycles multiple cards, because all the recycles happen simultaneously as a single instance. Nuances: - For Karma to trigger multiple times, the effect would need to be worded as a reflexive trigger that recycles cards one at a time in sequence (like "do this 4 times") - Vi works well with Karma because Vi recycles one card at a time, triggering Karma multiple times

Ruling: Fox Fire locks in its targets when cast. At resolution, the caster selects a combined 4 power or less from those previously selected targets to destroy. If no targets meet the criteria anymore, the spell resolves doing nothing (spells never fizzle in Riftbound). Sequence: - Fox Fire is cast and targets are selected (must be 4 Might or less at this time) - Other spells/abilities can be added to the chain - When Fox Fire resolves, the caster chooses which of the original targets to destroy, up to a combined 4 Might - If all original targets are now above 4 Might, Fox Fire resolves doing nothing Nuances: - Targets cannot be re-chosen at resolution if original targets become invalid - Zero is a valid number for "any number" effects, so choosing no targets is legal - Ravenbloom Student triggered abilities only go on the stack after Fox Fire fully resolves, so they cannot pump themselves before Fox Fire resolves - Fox Fire cannot target units on a different battlefield than where it was played if the original targets become invalid

Ruling: Yes, when Fox-Fire is played from hidden, it can only target the battlefield it is on because it chooses a target. Nuances: - The limitation applies to effects that choose, based on the FAQ - You don't need to see the word "choose" explicitly written on the card for it to be considered a choice - Choosing a game object is targeting rulewise, though some cards may say "choose" without issuing targeting - The FAQ is the most up-to-date source for this ruling

Ruling: The unit survives with 1 HP. Garen's passive ability is always on and applies immediately when he arrives at the new location, giving the +1 might bonus before any reactions resolve. Sequence: - Garen moves to the battlefield (movement doesn't go on the chain) - Garen's passive ability immediately applies at the new location, giving friendly units +1 might - Attacking player passes on reactions - Defending player plays reaction spell dealing 1 damage - The unit has 2 might total (1 base + 1 from Garen), takes 1 damage, survives at 1 HP Nuances: - Passive abilities (worded as statements of fact) are always on and don't go on the chain, so they can't be reacted to - Triggered abilities (worded "When X, do Y") and activated abilities (worded "Cost: Effect") do go on the chain and can be reacted to - Movement itself doesn't go on the chain, so you can't react to the movement before passive abilities apply - If the ability were worded "When I move here, other units have +1 might" (triggered ability), it would go on the chain and could be reacted to, resolving differently

Ruling: The Recruit tokens survive. Units are healed immediately after units with lethal damage are removed from combat, before any cleanup occurs that would remove Garen's passive effect. Sequence: - All combat damage is assigned simultaneously - Units with lethal damage are removed (Garen dies) - Units are healed (Recruits go back to full health) - Cleanup occurs (Garen's effect wears off) Nuances: - This ruling is specifically detailed in the FAQ - The healing occurs before any board-state effects reapply and before any triggers enter the chain - Even if a Deathknell effect triggers, the cleanup after it would not kill the tokens before healing under the updated rules

Ruling: When Get Excited is countered by Windwall, the discard does not happen because the discard is part of the spell's resolution, not a cost. Nuances: - If discard were a cost, it would happen before the spell could be countered - Since discard is part of resolution, a countered spell does not resolve and therefore the discard does not occur

Ruling: Yes, the attacker will need to recycle one rune to pay for Deflect when Green Yasuo's attack ability targets the Deadbloom Predator.

Ruling: Orange Master Yi survives. Flash does not cause the combat showdown to end, and the combat continues to full resolution including cleanup. Sequence: - Green Yasuo deals 6 ability damage to Orange Master Yi during the showdown - Green Yasuo is moved to base with Flash - Orange Master Yi remains at 8 might (6 base + 2 from defending alone) with 6 damage marked - Combat showdown continues to completion - During cleanup, damage is healed before "defender" status is cleared - Master Yi heals to full while still at 8 might - After healing completes, defender status ends and Master Yi returns to 6 might with no damage Nuances: - Once a combat showdown starts, it doesn't end until fully resolved, even if one player no longer has units at that battlefield - Passive effects like the +2 might from defending alone (and Shield) remain applied until after the combat has fully resolved and units lose defender status - Damage is healed before defender status is cleared during combat showdown cleanup

Ruling: The defending unit strikes back for its full 10 power during combat resolution. Dealing damage does not change the might of a unit. Both units die in combat resolution (Yasuo takes 10 damage, the defender takes 6 from the ability plus 6 from combat for 12 total). Sequence: - Yasuo moves to the location, initiating a combat showdown - Yasuo's "when I attack" ability goes on chain - Chain resolves: Yasuo deals 6 damage to the 10 might unit - Both players have an opportunity to play actions - Combat resolution: Players add the might of their units (10 for defender, 6 for attacker) - Both units die if no other effects were played Nuances: - Reactions (like Hidden Blade) can be played in response to Yasuo's attack trigger before it resolves - Actions (like Bullet Time) cannot be played until after the trigger resolves and players get the action window - When Yasuo's ability triggers and is added to the chain, the target must be specified immediately, not when it resolves

Ruling: Yes, the Mountain Drake heals before Yasuo can attack again. A showdown must fully resolve (including cleanup and healing) before a second showdown can begin, even if units leave the battlefield during the first showdown. Sequence: - Yasuo moves into Battlefield A and deals 6 ability damage to Mountain Drake, starting a showdown - Player A casts Ride the Wind to move Yasuo to Battlefield B - Player B passes focus - Player A passes focus - The first showdown ends and cleanup occurs (all units heal) - If Battlefield B is contested, a new showdown begins there Nuances: - Showdowns do not automatically end just because there is only 1 or 0 players in the battlefield; the showdown only ends when both players pass focus - When a second combat is created while a showdown is ongoing, it becomes "staged" and the turn player must resolve the already started combat first before addressing staged combats

Ruling: The Recruit unit token is returned to hand, then immediately ceases to exist because tokens cease to exist when put into any non-board zone (hand is a non-board zone). Nuances: - This effectively removes the token but does not count as "dying" in the game action sense, so it would not trigger "when unit dies" abilities

Ruling: When you react with Gust to an opponent's Discipline, Gust resolves first and returns the unit. The opponent still draws a card from Discipline even though the target unit is no longer present. Sequence: - Gust resolves first, returning the unit that was targeted by Discipline - Discipline then resolves as much as possible - The Discipline player draws 1 card (does not require information about the unit to draw) Nuances: - Spells always resolve as much as possible even if they lose their target - The arithmetic value change rules are for simultaneous positive and negative value changes (like Discipline and Smoke Screen used together), not for this interaction

Ruling: The Sand Soldier does not die. It disappears from the game completely and ceases to exist. For any effect that would track it, it did return to hand. Nuances: - If a token would leave the board for any reason, it ceases to exist - The token is not considered to have died, but it does count as having returned to hand for tracking purposes

Ruling: No, once targets are declared upon entering the chain, they cannot be redeclared. Gust will resolve with no effect if its target becomes invalid. Sequence: - Player declares target when playing Gust and adding it to the chain - If the target becomes invalid during resolution (e.g., might increases above 4), the target cannot be changed - Gust resolves with no effect

Ruling: Yes, Harnessed Dragon's kill effect still triggers even if the dragon is killed in response to being played. Nuances: - This differs from Anivia, which requires being "here" (on the battlefield) for its effect to resolve - If a unit is returned to hand (flashed back to base) in response to targeted damage effects like Comit or Void Seeker, that unit no longer takes damage

Ruling: Yes, you still need to kill a unit or gear to use the Exhaust ability. The exhaust ability is directly duplicated with all costs, restrictions, and effects. Nuances: - You can kill the Heimerdinger Inventor itself to satisfy the cost

Ruling: Heimerdinger kills himself when copying the Gold Gear Token's exhaust ability because he copies the costs of exhaust abilities as well as their effects. Sequence: - Heimerdinger's ability triggers on the exhaust ability - He copies both the cost (Kill this) and the effect (add power resource) - Heimerdinger is killed as part of paying the copied cost - The power resource effect resolves

Ruling: Heimerdinger copies ALL tap abilities from ALL friendly legends, units, and gear simultaneously. When you activate one of those copied abilities, you only activate that ONE specific ability, not all abilities at once. Nuances: - Heimerdinger copies the mana cost associated with the abilities (such as Viktor's pay 1 cost) - Even though multiple abilities are copied, you can only activate one of them when you tap Heimerdinger

Ruling: Heimerdinger can only activate one artifact ability when he exhausts, not all of them simultaneously. Nuances: - Even though Heimerdinger's text says he has "all" the abilities, he must choose which single ability to use when exhausting - The abilities are separate lines/effects, not one combined effect

Ruling: You only choose 1 ability when Heimerdinger taps, not all abilities simultaneously.

Ruling: Heimerdinger, Inventor copies all tap abilities from friendly legends, units, and gear, but you can only activate ONE copied tap ability per turn since activating a tap ability requires tapping Heimerdinger himself. Sequence: - Heimerdinger passively gains all tap abilities from all friendly legends, units, and gear you control - To activate one of those copied tap abilities, you choose which specific ability to use - You tap Heimerdinger (not the original source) and pay that ability's cost - The chosen ability resolves - You cannot activate another copied tap ability until Heimerdinger is readied Nuances: - Viktor, Leader does not have a tap ability (only a triggered ability), so there would be nothing to copy from him - If you control multiple sources with tap abilities, Heimerdinger has all of them simultaneously, but can only use one per turn unless readied - You tap Heimerdinger to pay the tap cost, not the original permanent with the ability

Ruling: Once targets are chosen for a spell, they will not change even when the original target becomes invalid. The player is not forced to retarget their own unit. Nuances: - This applies when Hextech Ray originally had two valid targets and one becomes invalid after targeting

Ruling: Yes, Hidden Blade kills the unit before damage is calculated. Spells resolve before combat damage is dealt. Sequence: - Hidden Blade is played during showdown - The spell resolves, killing the target unit - Combat damage is dealt (after the showdown is over) - Since the unit is already dead, it does not deal or receive combat damage

Ruling: When Hidden Blade is played from hand, it can target a unit at any battlefield. When played from hidden, it can only target units at the battlefield where it was hidden. Nuances: - Hidden cards that require a target must pick from the battlefield they were hidden at, unless the card explicitly restricts targeting in a way that makes it impossible to target something on the current battlefield (like requiring a target at a different location) - Saying "any battlefield" would be equivalent to "a battlefield" and doesn't prevent targeting the current battlefield, so it wouldn't allow targeting other battlefields when played from hidden - If Hidden Blade is played from hand targeting a unit at one battlefield, and that unit moves to a different battlefield before resolution, the target is still valid because it's still at a battlefield

Ruling: Yes, the opponent can play Gust before the Deathknell trigger resolves. Sequence: - Hidden Blade resolves, killing Undercover Agent and drawing two cards - Deathknell trigger goes on the chain - There is an opportunity window for Reactions (like Gust) before the Deathknell resolves - After Reactions are played or passed, the Deathknell trigger resolves

Ruling: Hidden Blade will still draw 2 cards, but Baited Hook will not summon a unit. Nuances: - Hidden Blade references "its controller" which only requires the target was valid at resolution, not that the unit actually died - Baited Hook references "the killed unit" and its might, so if no unit died (protected by Zhonya's), no might value exists and the effect cannot resolve - Both effects will still reveal the top card of deck as part of resolution

Ruling: 'Its controller' refers to the controller of the killed unit, not the controller of the battlefield. Nuances: - The word 'unit' is the subject of the sentence, while 'at a battlefield' is a descriptor, so 'its' grammatically refers back to 'unit' - If it referred to the battlefield controller, the card would be poorly designed since when played as a hidden reaction during showdown, you would already control the battlefield, making the wording unnecessarily convoluted instead of just saying 'draw 2'

Ruling: Yes, the opponent draws 2 cards. The draw 2 effect on Hidden Blade is not dependent on the unit being killed; it triggers when Hidden Blade resolves on a valid target. Hidden Blade can "look back" at the unit's characteristics before it moved zones. Nuances: - If the unit is bounced to hand by another effect before Hidden Blade resolves, no draw occurs because the target becomes ineligible and Hidden Blade cannot check the controller. - If the unit is moved to base by another card (like Fight or Flight) before Hidden Blade resolves, no draw occurs for the same reason. - If the unit is moved to another battlefield before Hidden Blade resolves, it remains a valid target (assuming Hidden Blade was played from hand) and the draw still occurs.

Ruling: When Hidden Blade resolves but its target is no longer at a battlefield (having been recalled to base), the controller does not draw cards because the unit is no longer a legal target and "its controller" cannot be determined. Sequence: - First Hidden Blade resolves, kills the unit, and Sett legend ability saves it by recalling it to base - The controller draws 2 cards for their Hidden Blade (the unit was a legal target when that spell began resolving and information can still be referenced) - Second Hidden Blade resolves, but the unit is now at base, not at a battlefield - The unit is no longer a legal target, so its information cannot be referenced - "Its controller" is meaningless and no cards are drawn Nuances: - If a unit is saved by an ability during Hidden Blade's resolution (like Zhonya's), the controller still draws because the target was legal when resolution started and the unit remains on the board - The key distinction is whether the unit becomes an illegal target before resolution starts versus during resolution - Target legality is checked when the spell starts resolving

Ruling: When Hidden Blade's target becomes illegal (moved out by Flight or Fight), the spell resolves but does nothing. The controller does not draw 2 cards because there is no legal target to determine "its controller" from. Sequence: - Hidden Blade is cast targeting Mindsplitter - Flight or Fight is played in response and resolves, moving Mindsplitter out - Hidden Blade resolves with an illegal target - The damage/kill effect doesn't resolve (no legal target) - The draw 2 effect doesn't resolve (no legal target means no controller to reference) Nuances: - If the unit were saved by Zhonya's or similar effects instead, it would remain a legal target and the controller would still draw 2 cards (even though the unit doesn't actually die, as the death is replaced) - The unit doesn't need to die for the draw to happen, but it does need to remain a legal target

Ruling: You must decide to use Sett's replacement effect before drawing cards. Sett's ability replaces the "kill" portion of Hidden Blade, and replacement effects intercede during execution of a game effect before subsequent effects resolve. You still draw 2 cards after using Sett to save the unit. Sequence: - Hidden Blade begins resolving - The "kill a unit" effect is about to execute - Sett's replacement effect must be decided at this point (it replaces the kill) - If Sett is used, the unit returns to base exhausted instead of dying - The "draw 2 cards" portion of Hidden Blade then resolves - The controller of the saved unit still draws 2 cards Nuances: - The draw happens because the unit was still on the battlefield when Hidden Blade checked for "its controller" - replacement effects don't remove the unit from play during resolution - This is different from using Retreat or other reaction-speed spells that move the unit off the battlefield before Hidden Blade resolves - in those cases, no cards are drawn because the controller cannot be determined - Zhonya's Hourglass works the same way as Sett - you still draw because the unit is checked while still on the battlefield during resolution - The draw is contingent on killing the unit (attempting the kill effect), not on the unit actually dying

Ruling: No, you cannot pay for the revealed Ekko's accelerate cost with the killed Ekko's deathknell runes. The revealed Ekko will be played before the deathknell resolves. Sequence: - Hook kills Ekko, triggering its deathknell (goes to pending chain) - Hook reveals Ekko from top of deck (goes to pending chain) - First Ekko's deathknell is finalized and goes on the chain - Second Ekko is finalized and plays immediately (because it's a permanent) - First Ekko's deathknell resolves from the chain Nuances: - The order in which items are added to the pending chain doesn't matter in this case, because permanents are played immediately when finalized, while triggered abilities go on the chain to resolve later