Suguru is hired as Bad Luck's keyboard player. Though he usually fakes being polite to others, young Suguru is quite similar to his cousin, Tohma Seguchi, despite his unfortunate proclivity for being controlled by others. While only sixteen years old, he has incredible talent - and knows it. Suguru knows Eiri Yuki's past as well, but it seems that Yuki also knows a bit about Suguru himself: he has commented before about Suguru "hiding his real identity". He is quite short for his age, something K and Tatsuha constantly tease him about.
Suguru's favourite food is melon, he also loves Pocky (caramel), but refuses to eat it around others because it makes him hyper. He can't handle very spicy food. His hobbies include classical music appreciation and playing videogames (particularly RPG's).
Bad Luck's manager K often teases him about his short height and enjoys doing things to embarrass him, such as sneaking up on him and lifting him up, or speaking to him completely in English just to confuse him. He secretly has a crush on Hiroshi Nakano. Suguru and Tatsuha have hung out together since they were eight years old, although he finds Tatsuha a bit annoying.
Suguru's skill at playing the synthesizer is unrivaled, a result of his precociousness and drive. Shuichi, lead singer of Bad Luck, often gets a little jealous of Suguru being so talented.