Final Fantasy X/Aeons

Yojimbo:

Yojimbo is a poweful aeon that has godly evasion but lower than average health and defenses. You have to pay an amount of gil (that you decide) for him to attack. Lower gil results in him commanding his dog to attack, Daigoro. More gil makes him use Kozuka, throwing 3 daggers that will either hit 1 or all enemies. Even more gil will result in Wakizashi, a powerful katana attack that can also hit 1 or all enemies. A lot (and I mean a LOT) of gil results in Zanmato. He draws a katana from the belly of hell, unsheathes its shimmering blade, casts away the scabbard, and lauches a spinning lateral slash at the enemies. A gust of wind will promptly decapitate them. The is a infallible 1-hit-kill attack that works on bosses too, either killing them or sending them into their next form!

It should be noted that all his attack are automatically Penetrating. You cannot teach Yojimbo any abilities. His Overdrive is only increase probability of using Zanmato.

"Yojimbo" is "bodyguard" in Japanese, fitting for a pay-per-kill aeon.