I have a unit equipped with Last Rites and I control a Battlefield. When exactly can I play the unit, or does the timing not matter since the condition has been fulfilled?

To clarify the timing for playing a unit using the ability on Last Rites:

When the condition for the ability on Last Rites is met (i.e., you conquer a battlefield), you may play a unit from your trash. According to RiftJudge FAQ #1014, because the ability does not specify a restricted window for playing the unit, you are permitted to play it ignoring normal timing restrictions.

Sequence of Events:

1. Trigger Condition Met: You conquer a battlefield. The "When I conquer" ability on Last Rites triggers.
2. Adding to Chain: You choose whether to place this triggered ability on the chain. If you choose to do so, it is placed on the chain as a pending item.
3. Resolution: When the trigger resolves, you choose whether or not to play a unit from your trash.
4. Playing the Unit: If you choose to play a unit, it immediately goes on the chain as a pending item.
5. Finalization: In the cleanup after the trigger resolves, you finalize the unit (choose where to play it, pay its costs). The unit then immediately resolves and enters play.

Important Nuances:

• Cost Payment: You must be able to pay the full cost of the unit you are playing from your trash.
• Presence Requirement: Per RiftJudge FAQ #9015, the source of the ability (the unit equipped with Last Rites) must be present on the battlefield at the moment the conquer event occurs for the ability to trigger. If the unit leaves the board before the event is finalized, the ability will not trigger.
• Timing: Unlike standard unit deployment, which requires an Open State during your Main Phase, this specific ability allows you to play the unit even during your opponent's turn if the trigger condition is met, as it bypasses standard timing restrictions.

Note: I could not fully verify this ruling against the retrieved rules.