When a unit with a triggered ability (like Brynhir) enters play, can you respond with Reaction speed cards before the trigger resolves, and does removing the unit prevent the trigger from resolving?

Ruling: When a unit with a triggered ability enters play, the ability goes on the chain and both players can respond with Reaction speed cards before it resolves. Triggered abilities always resolve regardless of whether the unit is killed, bounced, or banished.

Sequence:

• Unit enters play immediately
• Triggered ability goes on the chain
• Active player can play Reactions or pass
• When active player passes, non-active player can play Reactions
• Once both players pass, the chain resolves
• Triggered ability resolves last (as it was first on the chain)
• Once the ability resolves, its effect applies for the rest of the turn

Nuances:

• Only Reaction speed cards can be added to the chain; Action speed cards are too slow
• Players hold priority and can play multiple Reactions before passing
• Players can continue adding Reactions as the chain resolves (after each item resolves, the owner of the next item gains priority first)
• Triggers always resolve even if the unit is removed, though effects referencing "here" or similar may not execute if the referent is undefined
• Triggers without referential information (like "here", "me", "my") will fully execute even if the unit is gone