The legendary samurai epic by Kazuo Koike and Goseki Kojima has a blood spilling cast:
The former executioner of the Shogun. Was framed by Retsudo of the Yagyu Clan and sentenced to die. Instead, Itto takes his son Daigoro with him on a quest to avenge themselves against the Yagyu.
Itto's three-year-old son, who accompanies his father on their wanderings upon the assassin's road. In spite of his age, Daigoro often serves as an asset during many of Itto's assassinations, prompting opponents to lower their guard or even restrain their own efforts to avoid hurting the child.
- Badass Adorable - People remark about how cute Daigoro is a lot. He helps his father kill people. Crosses into Killer Rabbit on a few rare occasions.
- Cheerful Child
- Consummate Professional - Daigoro learned from the best, after all.
- Creepy Child - invoked in-universe.
- Dark and Troubled Past
- Death Glare - why cute lil' Daigoro is frequently described as creepy
- False Innocence Trick
- Family Honor
- I Gave My Word
- In Harm's Way - Follows his father's example.
- Kid Samurai - Daigoro is frequently remarked to be a very good one.
- Morality Pet
- Wise Beyond Their Years - Daigoro's a very mature little four year old. Itto's a good parent if anyone is to judge by how well behaved and intelligent this four year old is. There's even a storyline that focuses on how different Daigoro is from other children.
- In some ways, Daigoro is considered to be his father's equal, if not outright superior. He has often been described as having the Shisogan or "The eyes of a swordsman able to place his heart in the nothingness of Mu," an attribute many lesser swordsmen throughout the story aspire to. And Daigoro has them at the tender age of three.
The head of the Ura Yagyu, the Shogun's assassins. Retsudo uses his position to secretly control the Shogunate from the shadows. In order to assume more complete control, he schemed to acquire Itto's position by disgracing him and his clan, which Retsudo succeeds in. In spite of his scheming nature, Retsudo is a master swordsman and Itto's only true equal throughout the series. He is also a master strategist and is skilled at several ninja tactics as well.
Abe no Kaii
The Shogun's food taster, who is personally responsible for inspecting the food that is served to the Shogun for any sign of poison. Because of this, Abe no Kaii is an expert on poisons and, thus, an expert on poisoning others. He is assigned to help Retsudo kill Itto by the Shogun, but secretly schemes behind their backs to kill both Itto and Retsudo thus allowing him to become the force controlling the Shogunate behind the scenes. Unlike Retsudo, who is at least a Bushi and holds himself to certain standards of honor, Abe no Kaii holds nothing but disdain for the warrior code and will stoop to use any tactics to get what he wants and is also a gutless coward who always thinks of himself first.
- Alas, Poor Villain
- Bald of Evil
- Dirty Coward: He runs and screams in terror at the drop of a hat and is deemed by both Itto and Retsudo to be too pathetic to be worth killing. This lasts all the way up until Retsudo successfully disgraces him by burning the kitchens of the Shogun's castle, which results in Kaii being sentenced to seppuku. He's so terrified at the thought of cutting his own stomach that he initially tried to spare himself the pain by swallowing his own poison, but is too cowardly to even do that. By the time he's actually brought to the execution, he's a quivering, crying mess.
- Foil: To both Ogami and Retsudo.
- Gonk: As close as this series gets to it. He's fat and ugly, complete with puffy lips and sadistic leer that he throws around at everyone.
- The Hedonist: Abuses his position and uses his mastery over drugs to enslave several women, who he then forces to have sex with him on a regular basis. He otherwise tries to live it up in whatever way he can.
- Non-Action Guy
- Not-So-Harmless Villain
- Master Poisoner
- Self-Made Orphan
- Spanner in the Works: A massive one for the final arc. He forces Itto and Retsudo to postpone their final reckoning no fewer than three times. First, he forces an end to Itto's battle with Retsudo and his Yagyu army by triggering a massive flood through Edo that forces Itto to sacrifice the arsenal of bombs he'd bought using his assassination fees in order to create a makeshift dam. The second time, he finds Itto's and Retsudo's swords, which they'd left behind, and coats them with poison, forcing them to put off their final duel yet again. Then, he steals the Yagyu Letter from Itto and Daigoro and brings it to the Shogun, which leads to Retsudo being imprisoned, forcing him and Itto to postpone their duel again. It also gives Retsudo reason and time to call in all his Kusa, which ultimately results in Itto's death.
- Squick: Practically oozes this trope. At one point, he decides that he's thirsty, but there's no well or other source of water nearby. So he orders his female companion to pee so that he can drink her urine instead. Later on, when he's waiting at a temple for Retsudo to arrive, Kai pretends to hang himself so that Retsudo won't kill him. But, in the process of waiting, he ends up urinating while hanging, then he gets hungry, so he climbs down to get something to eat. While doing that, he reasons that, since urine is salty, it'll make a good seasoning for rice. So he decides to make himself riceballs...by rolling the rice in the piss that was already on the floor. Seriously, this guy is disgusting.