When playing Cruel Patron and paying its cost by killing a Recruit token, does this create a chain that can be reacted to? Can you kill the Recruit with a facedown Hidden Blade, draw 2 cards, and still play Cruel Patron? If the death triggers abilities like Deathknell, when do those resolve and can they target Cruel Patron?

Ruling: Killing the Recruit token is a cost, not an ability, so it doesn't use the chain and opponents cannot react to it. You cannot use Hidden Blade to kill the Recruit instead because costs are paid as part of playing the card. When a unit dies as a cost and triggers abilities like Deathknell, those triggers are added to the chain as pending, Cruel Patron resolves immediately (since permanents resolve immediately upon being added to the chain), and then the pending triggers are fully added to the chain afterward.

Sequence:

• Start playing Cruel Patron
• Pay the cost, which includes killing a unit
• Cruel Patron is added to the chain AND the death trigger condition is met
• The trigger is added to the chain as pending (since it occurs during playing another card)
• Cruel Patron resolves immediately
• The pending trigger is now fully added to the chain

Nuances:

• A hypothetical targeting Deathknell ability could target Cruel Patron because it resolves before the trigger is fully added to the chain
• You can only kill a unit at the battlefield as a cost if there's at least one more unit there keeping control of it
• The goal is for finalized items to never be on the chain above a permanent