Does Darius get the +2 on Challenge if Challenge is the 2nd card played?

Ruling: No, Darius does not get the +2 bonus if Challenge is the 2nd card played.

Sequence:

• Challenge is played as the 2nd card
• Challenge causes units to deal damage to each other before it resolves
• Challenge resolves
• Darius's trigger goes on the chain during the cleanup that follows
• If Darius has 5+ damage marked on him, he dies in step 2 of that cleanup
• The trigger still resolves but whiffs because Darius is no longer a valid game object to receive +2 Might and ready

Nuances:

• Darius's trigger occurs after the second card is resolved in a turn, not during its resolution
• Even if Darius dies, his trigger will still linger on the chain and resolve, but it will have no effect since there's no valid target