I thought it was XP too but when you have summons.etc... they seem to share the exp as you 50, summon 50, summon 15 regardless of dmg caused, or so it seems.
Also, sometimes my other chars cause dmg and get 5 or 0.
I guess one good way to find out is to remember what your XP is before a battle, and what the crowns say, then see if your XP went up by that much.
Guess I am going to try that now
