The aasimar, eager to win and redeem the cause of Celestia, takes a 5' step to enter the arena at 0N0E, (if necessary, loads his light crossbow) and fires his light crossbow at the duckbunny. That done, he drops his light crossbow. (If he has an action left, he draws his longsword.)
Q: What does a duckbunny look like? Any significantly noticeable natural weapons (Claws like daggers, teeth like swords, horns like giant's spears, etc.)?