While I've never personally done it, I've experimented and it should be quite possible to kill Sudiva. A well-trained Greater Dragon can tank her. She has 99 in every resist, though, which is why most hits only do a single point of damage. Therefore you need necromancers spamming Corpse Skin to reduce her fire resistance. And I do mean spamming it, since she has something like 160 resisting spells skill, cutting the duration of each Corpse Skin to almost nothing.
With her fire resistance lowered, mages cut loose with fire spells, paladins use Consecrate Weapon, and so forth to hammer her. Direct damage such as Armor Ignore and the critical hits from Lightning Strikes also do full damage. With enough time and patience, it ought to be entirely possible for a decent group of people to bring her down in a reasonable timeframe.
