I.
The first lesson Mugen ever got about honor was from his old man.
"Try not to hit women," he told his son once. Mugen has forgotten, now, what they were even doing; he thinks mending the fishing nets. They did that a lot, when his father was alive to go out fishing. When he wasn't fishing he was gutting fish to sell, and when he wasn't selling them he was mending his nets. And if he wasn't mending his nets he was passed out dead drunk over a table at the bar down the street, or sleeping it off in the back room.
Sometimes when he's bored, Mugen picks up a piece of string and before he knows it he's got half a net without even thinking that's what he was gonna do. Even now.
"Try not to hit women," his father told him once. "They're usually weaker than men. Soft hands. Harder for them to fight back. So you shouldn't hit 'em."
Mugen had thought back to a million past nights. His mother crying out, his father red-eyed with drink; the bloodstains on the collar of her kimono in the morning and the too-hard set of her mouth.
He once saw his mother lie for his father. The only moment of tenderness between him. Is that honor? He thought. Lies to protect the guilty, as long as the guilty is yours?
"Sure," he responded, "whatever you say." Fucking liar, he thought, but didn't say out loud. His father may have only beat up on his mother – on women – when he was drunk, but Mugen was free game all day, every day.
That was when he was little. Once he got older, and his hands got hard and his violent joy found a blade to carry it, his father didn't dare raise a hand to him any more.
That was too late for his mother, though.
"Mugen," Fuu says, and he stops remembering. "Hurry up or the food will get cold."
Mugen looks down at his hands, the string knotted into perfect square traps. "Shut up," he says, pitching the past into the fire. The cords of the string take a minute to catch; he watches until they do. Then he stands. "If there's none left for me I'm gonna steal yours, you damn pig."
The first lesson Mugen ever got about honor was from his old man. Which was just proof that honor only counts when you want it to.
II.
The second lesson on honor Mugen got was actually from Fuu. A coin toss decided his fate and she would not let him walk off.
Mugen probably could have. Mugen definitely could have. Fuu doesn't come up to his neck and he wouldn't even have to cut her, just hit her good with the flat of the blade and walk in the other direction.
He thinks about it. He envisions it.
He hears his father tell him not to hit women and looks down at her, so young and so soft and yet somehow strong.
This is stupid, he thinks, and decides that he'll go along with this fucking stupid girl for now because she did save his ass and the fish-face is going with her, and Mugen wants to try killing him again real bad.
Honor. Who needs it? Mugen just needs to do what he wants: it's simple as that.
And later, when it gets complicated, he thinks back to this thought and knows that it is truth and it is lie.
III.
The third lesson Mugen got about honor was from Kohza.
Mugen had known going in that Mukuro was a snake, the kind of criminal that even criminals avoid. That was kind of why he'd gotten on the ship to begin with. Mugen lives pretty close to death and sometimes it's refreshing to be even closer. Keeps him sharp, strong.
Which proves that honor is a lie and all of life is a con. Also, that women are about as soft as rock. Mugen doesn't kill her, because that's what she wants, and once he knows that he knows how to hurt her as bad as anyone ever could.
After the boat; the cliff; the beach; Mugen can only draw one conclusion: partnerships don't amount to shit. Promises are broken as easily as wood burns.
You had better rely on your own damned self if you want to get anything out of your miserable life.
But Jin killed Mukuro, and Mukuro was Mugen's demon. And there's something inside of that thought that Mugen can't quite reach, something important and somehow painful. Some lesson he can't make sense of.
IV.
The fourth lesson is from a lot of people. It's given to Mugen in bits and pieces, meted out along the dusty roads on the way to Edo. It's learned both in spite of and because of bloodshed and blood thirst; learned from learning that other people have reasons for what they do as much as he does, and some of the time they're even good reasons.
Maybe Mugen doesn't really get why Fuu is willing to go so far for her Sunflower Samurai, but he knows what it's like to draw justice from the face of his father. Mugen's father hit him, so Mugen hit back. But Fuu's father just left, and so Fuu needs to see his face to know what justice she can get.
And Jin, the fish-face? Jin is silent and pale, and weirdly empty. But when he fights he is full of life, brimming over with power. It's like the real Jin is hiding somewhere, like a kid under a blanket waiting for the argument to die down, or like a hidden riptide off the beach. There's more to Jin than Mugen can understand or explain, he knows. But damn if their battles aren't among the best things that have ever happened to him.
V.
The fifth lesson comes when he cuts Fuu loose, and he tells her to run and she goes, goes after her Sunflower Samurai. And she doesn't do it because she wants to leave Mugen, but because she needs to. This enemy is his, this ugly bastard belongs to Mugen, like the other guy down at the dock belongs to Jin. Their respective pasts turning their red eyes on them at them, raising their fists to them. Mugen has never been a paragon of fairness, but even he knows that letting his mistake fuck up Fuu's life is just wrong. He doesn't have better words for it than that.
So he cuts her loose, and he tells her to run and nothing else, and he doesn't watch her go but he listens, listens to the slap of her sandals as she goes into the dusk to find the face of her father. He keeps his eyes on the malformed little pissant who had her tied up. He thinks of Jin on the dock less than an hour ago, telling Mugen to run, facing his own enemy like a wall.
Honor is weakness, lies, excuses. But today Mugen learns that honor is just knowing what you won't allow to happen. And then making sure that it doesn't.