"The archmages practice the forbidden arcane arts."
Arcanist is a Job in Final Fantasy Tactics A2: Grimoire of the Rift, usable by the Nu Mou only. The Job specializes in using destructive Arcane Magic, with abilities learned from rods. Arcanists have a large base MP pool, which when combined with their advance spell portfolios, makes them a potent foe against an enemy in an extended battle, but with all of these, the Arcanist stats are very low, so it might not be a good idea to level up as one. They have very low HP and low Evasion, though with the Drain and Halve MP abilities, an Arcanist can heal itself with every attack and essentially never die, unless hit by a Death effect or a very powerful attack.
Perhaps the most obvious tactic would be giving all your units or just the Arcanist equipment that grants immunity or absorbs Darkness, in which the Arcanist would function exactly like a Scholar. If this method is used, the Arcanist will always be able to heal himself and his allies, due to the skill Lvl ? Shadow Flare.
Notable Arcanists in the game include Duke Snakeheart, a Boss of Duelhorn, and Madreth, clan leader of Nu Mou Nobles.