After Dirge’s ability resolves, does the bonus change if the number of characters in my opponent’s KO area changes later in the turn?
[Source: WotC]
No. you count the number of characters in your opponent’s KO area when the ability resolves. After that, even if you KO another character, the attack bonus won’t change.
If you attack with Dirge and it does more than enough attack damage to KO the defender,
Steamroll’s ability will work, but Dirge’s ability won’t trigger. If Dirge does exactly enough damage to KO the defender, Steamroll won’t do anything.
If my opponent has a combined
Volcanicus in their K.O. Area, and I flip Dirge to Alt Mode, does Dirge get +1 or +5 attack?
[Source: WotC]