Soujiro the Tenken, smiling little psychopath and most skilled of Shishio's Juppongatana. Unlike the other really strong characters in Rurouni Kenshin, he was too young to have fought in the Bakumatsu. He had his own personal Hell that forced him to become strong, and, like Kenshin, he paid a price from his humanity for that strength.

I find Soujiro to be a rather interesting character, and more sympathetic than I would have expected.