Possible Spoilers for Volume Seven
Nothing related to the main plot, however.

Name: Harada Sanosuke
Age: 24
Gender: Male
Rank: Captain of the Tenth Unit

Appearance: He has short, shaggy hair on the top of his head and longer hair pulled into a bun on the bottom of his head. With mysterious eyes and a sly grin, he has a certain boy-ish charm about him.

Personality: He seems to act typically like any other boy - usually only concerned with fighting and flirting (so to speak). In the manga, though, he seems to prefer boys over women, especially Kamiya. (Remember, Harada does not know that Kamiya is a girl. =P) However, he is quite capable of being serious when the situation presents itself, though he won't keep such a serious act longer than needed.

Past (Manga): In the past, Harada claims to have attempted seppuku, and he does have the scar to back that story up. However, the manga does not travel much into his past.

Relative History: Coming soon.