- The Scotsman to Jack. Like Jack, he is a frighteningly skilled wandering warrior with no name, an enchanted sword, and is talented in a plethora of fighting techniques. However, in contrast, he is rude, boisterously loud, shows little respect to his enemies, and could really use a shower and a toothbrush. They're both good guys and become allies after a 24-hour battle and a quick fight with some bounty hunters.
- The Scotsman also becomes this to the High Priestess of Aku by Season 5. They both conceive many daughters and raise them to be Action Girls, but the High Priestess has no love or kindness for her children and raises them to become murderous Social Darwinists devoid of any of those traits; the Scotsman on the other hand clearly put a lot of love and loyalty into all his daughters, and they're much psychologically healthier as a result.
- The High Priestess is this to Aku himself to some extent. While Aku is a demon who is Made of Evil, but still manages to retain some comedic traits despite generally being a total monster who has turned the Earth into a Crapsack World, the Priestess is a human with absolutely nothing even remotely human about her personality. When you make Aku look like a pretty cool guy in comparison, it's really time to rethink your whole life.
- Ashi to the Scotsman's wife. They both have romantic relationships with the two toughest warriors in this series; they both spend much of their initial speaking lines hurling insults at the heroes; they can both be very sweet, yet quick-tempered, and getting on either one's bad side is likely the last thing you'll ever do, and they're both shown to be one-woman armies, able to Curb Stomp entire actual armies and come out completely unscathed. However, Ashi is a slim and attractive brunette of (presumably) Asian descent whereas the Scotsman's wife is "stout", red-headed, not nearly as good-looking (besides to her husband), and is most definitely Scottish.
- Most obviously, Ashi starts out as Jack's enemy, trying to kill him in a blind rage out of her programmed loyalty to Aku, and ends up befriending him; the Scotsman's wife, on the other hand, initially warms up to him, only to be last seen chasing him down in a blind rage after he innocently presses her Berserk Button.
- The Omen to Ashi. The Omen wanted to crush Jack's hope and convince him to commit suicide, while Ashi convinces Jack that it isn't too late and to not give up.
- While Scaramouche the Merciless has some similarity to X-49 (both are robotic assassins with a love of jazz music), Scaramouche is the opposite of the other robot in every way. Scaramouche used magic and blades, X-49 used firearms. Scaramouche was loud and obnoxious, X-49 was quiet and reserved. Scaramouche dressed in a garish and loud purple trenchcoat, X-49 always wore conservative black dress suits. Scaramouche led Jack to him, while X-49 hunted Jack down. Not to mention that Scaramouche is proud to be a professional murderer, while X-49 wanted to quit killing people for Aku. Oh, and Scaramouche survived getting sliced apart by Jack, while X-49 died from that same fate.
- Aku is very much the exact opposite of Jack. While Jack seeks to do good wherever possible, even at risk to his well-being and goal of returning to the past, Aku always seeks out any action where he makes life miserable for others — even if it would be to his disadvantage in the long run. Their colors and designs likewise contrast as well - Jack is a humble prince in all-white robes who is selfless, empathetic, dutiful, and the epitome of an honorable man, while Aku is an all-black demon-sorcerer who is selfish, callous, treats the world as his toy box and the epitome of pure evil. Likewise, they also have opposing meaning in their titles — Jack's is "Samurai", which is generally associated with a humble and honorable warrior, while one of Aku's titles has him call himself a "Shogun", which is more in line with a ruler and supreme commander of an army.
- Season 5 in particular highlights their different reactions to their stalemate: while Jack forces himself to keep moving and fighting for mankind, Aku completely gives up on beating Jack and retreats from the public. Notably, Jack's hallucinations damn Jack for his inaction, while Aku begins talking to himself to try and feel better about his failure.
Foil / Samurai Jack