All he does is smoking, fishing and reading. He never says a word, unlike his puppet Johnny. Even though it's Haibara himself talking (or is it?), Johnny often speaks of Haibara as "useless" or "totally dependent on me". When Johnny is taken, Haibara is rendered voiceless. He's (or they've?) been living in Narutakisou for the long time. Haibara's mysterious past is deeply connected with Kozue's and he really cares for her very much. It is because of her he actually speaks for himself - just once...