Shamo, Koroshiya 1 Recommendations
both protagonist are super strong martial artists and they live in a work full of sorrow and pain.. the underworld, where yakuza and other clans find their place. Both of the character show no mercy when they fight and even kill their opponent.
Considering the dark themed stories surrounded by the underground world of Japan, I could easily say that the series are quite alike.The rapid fight scenes, mafia/yakuza, art and insanity, all of them are present in both manga. Especially the beginning of Shamo reminds one of Koroshiya as a whole. An interesting read for sure.