Dragonball XenoVerse Ultimate Attack guide :

Using Cell as MENTOR/MASTER his Z-Soul and ultimate attack = 1381 damage

Using Cell as MENTOR/MASTER ultimate attack and other Z-Soul = 983 damage

Using other (Piccolo) MENTOR/MASTER cell Z-Soul and ultimate attack = 1246 damage

Using other (Piccolo) MENTOR/MASTER other Z-Soul and ultimate attack = 934 damage