So I finally got around to playing Riviera again and the amount of hits Disaresta is still confusing me. Is if it fully connects or not based off of the RNG, the amount of hp they have, the type of enemy, or something else?
It depends on how full the Overdrive bar is. Higher Overdrive level = more hits from Disaresta. Lost Seraph works like that too.
If I remember right, a full overdrive bar gives you 8 or 9 hits and the last shot is an AoE hit.