Sakurai the Cursed
@Plutonium - I just finished beating it with Ascendant, soo... :p
As far as sustain while ascending the tower, I just used the Blade of Awe and Hammer->(Book Ch. 2 if needed)->Dagger->(whatever you need to finish them off if still alive) every fight with the elementals, to keep topped off on both HP and MP. The minibosses are really easy, I don't think they need much of a guide.
For Yaphael, his rotation is:
Slight heal + crit and bonus buff -> 5-hit attack -> 5-hit attack -> avoidance buff -> nuke -> nuke -> repeat
So just do Staff->Book->Scythe->Wand to start, then Dagger since he'll shield after that, ideally you'd use food to make sure you survive the nukes since if you spend a turn shielding or using a pot you won't have time to use Hammer, but either way after the second nuke just repeat the process as he starts his rotation over from there.
For Ezrajal, his rotation is:
Slight heal + copy 100% of your defense/avoidance (not including MPM from Luk, but including buffs) to buff himself with -> 2-hit attack -> 2-hit attack -> blind -> nuke -> nuke -> repeat
You mainly just want to avoid having any avoidance/defense buffs active when he copies you, to avoid him buffing himself too much. That said, the strategy is largely the same; Staff->Book->Scythe->Wand to start, but use Shield after that rather than Dagger, followed by Hammer (or blind if you really need to) and then repeat, using a pot or food instead of Shield when it's on cooldown. You don't really need to worry about the blind because it'll wear off before you Wand anyway, but Zard Kebabs can be useful to buff your bonus back up if your damage is too low.
@blowthemandown - A couple people have beaten most of the challenges with level 20something characters, even NDA.