>>3608
My answer to this is always Shigurui.
Its in a chain of 'cruel jidai-geki', or nasty period drama stories about late Samurai Japan.
Similar works include 'Lone Wolf and Cub' or other works from Kazuo Koike and Goseki Kojima, or 'Satsuma Gishiden' or other works from Hirata Hiroshi, as well as post-Shiguri works like 'Ichigeki' by Matsumoto Jiro.

But of them, Shiguiri is by far my favorite for its focus and fidelity on telling a story about two motherfuckers that just hate one another and who constantly tear each other down within a feudal system built around performative sociopathy, actual sociopathy, and sadism.
Irako Seigen, one of the two protagonists, is a real glorious bastard of a character and Byronic hero that is as scummy as he is magnificent. Top 5 favorite anime characters, easily.