One might wonder why Darius hadn't learned Purify earlier and allocated his Skill Points into it, yet there were good reasons for that.
In essence, Darius was certain that many of his iterations must've specialized in Intelligence and this spell, turning him into an Undead Slayer. However, none of the three things Caesar had mentioned involved spells, hence why he chose to prioritize as he did.
Darius already knew how the spell system of Faust largely worked and even had plans of dabbling in the Magical Method once he completed his Journeyman Quest.
He was certain that with his Intellect and creativity as someone from modern Earth, he could think up far more unique and versatile spells. Of course, if he was feeling lazy, he could do some half-hearted work and have his Transmutation ability 'fill in' the rest.
