Phoenix Dive was likely not a "Fire skill" originally.
My point stands: it's a skill that benefits primarily from a skill school different to the one that it's learned from.
No amount of points in warfare will improve Phoenix Dive, because it never deals any damage to enemy armor.
It benefits from Pyromancer directly, since it's fire, and Aerothurge indirectly, since fire damages Magic Armor before Vitality.
