Zwei the ilvard Insurrection Boss 18: Montblanc
1She only has 3000 HP (lowest of any main story boss by a mile) but she can only be hit once per cycle. This fight can get annoying fast because if you mistime an attack, which is very easy to do, the zombies will dogpile you. After almost every hit she will do a big attack summoning kamikaze zombies and they have explosions that cover a massive range and are almost certain to hit for massive damage because they can combo you. To avoid this swap to Alwen and spam her earth magic to deconstruct the zombies. Otherwise she only has 3 major attacks. A dogpile that acts like a counter (or a standard attack if you try to get outside the ring of zombies), an array of lasers that do nothing if you stand in the center, and shockwaves that come from multiple directions but since you should always be in the center anyways the direction does not matter because the timing will always remain the same.