He has a very rigid and militaristic personality, with an attitude that you must be stern and be able to discipline yourself responsibly. Though he does have a softer side, he rarely allows people to see it, not at all open with trusting others to see a vulnerable side of him. He does not enjoy imposing his personality and ideas upon others, and has the highest respect for other lifestyles and ideas, despite disagreeing with the lifestyle as he never grew up that way. He has a passion for a family life when he is older, and wishes to be a father in the future.
After careful consideration, Buichirou's voice is most similar to Hades Aidones, from the anime Kamigami no Asobi. However most other roles filled by Daisuke Ono is similar to the pitch I imagine for this character. Other interpretations however are welcome!