Susumu is my 2nd favorite character. (I'm sure you were just dying to know that)

Seiyuu: Sakurai Takahiro

A very enigmatic character, Yamazaki Susumu is held in high regard by Hijikata. He is a shinobi (basically like a ronin, only a ninja instead of a samurai, from what I've been told), and gathers information both by night and by day. At night he sneaks around in conventional shinobi style to find out what he can from the outside, but in the day, he dons a kimono and powders his face, transforming himself into a [very convincing] woman (and occasionally his sister!) so as to collect information from the inside. (Scroll down for a picture of what he looks like as a girl)

He has a cold, indifferent attitude to those around him, particularly his peers and people he considers weak (and a halfwite, i.e. Tetsu). When speaking to Hijikata, however, he is extremely respectful. It is clear that he has Hijikata's complete trust. He and Tetsu got off on the wrong foot - with Tetsu thinking that Susumu was a thief and Susumu mistaking Tetsu for a spy. Susumu rarely loses his temper, but he does so when Tetsu gets in the way of his work, going as far as to slap him.

Susumu is very serious about his work, and is willing to sacrifice his life for the Shinsengumi.

Ayumu is Susumu's older sister, and it is clear that Ayumu and Susumu are not on the best of terms. They are not even seen talking until the 8th episode, and even then, conversation between them was very terse. We find later that their parents died, and Ayumu raised Susumu. You'll have to watch the series to find out any more ~_^

Quotable Quotes: 'You're a halfwit.'(to Tetsu.)

'These escape wounds are dishonourable'