The Aku Infection
Episode numeral: XLIII
Original air date: 11/5/03
This episode features Jack becoming infected with Aku's sickness and being slowly taken over by him.
- Continuity Cavalcade: Many of the friends and allies Jack has made throughout the series up to this point are shown to him when the spirits of his parents remind him of his heroic efforts in the future during his struggle to fight Aku's essence over him. This includes, but not limited to: The Woolies, the Triceraquins, the "jump good" Wild Man and monkeys, Olivia and the rave dancers, and even the Scotsman!
- Fighting from the Inside: Gradually over the course of the episode, Aku's essence is overwhelming Jack. At the end, Jack is almost consumed. It isn't until he sees the spirits of his parents, who remind him of the good he has done, the allies he has made, and the fact that he isn't alone which finally gives him the strength to break the hold Aku's essence has over him and free himself.
- O.O.C. Is Serious Business: Aku's so sickly he doesn't bother fighting Jack at all. When he flies away, he doesn't shapeshift into an animal like he usually does, merely growing a pair of wings and retreating.
