Takateru is the eldest Kisshouin son and heir soon to succeed the family company in the future. The only sibling he has is his sister Reika who is younger than him by 7 years. Another prominent person in his life is his childhood friend, Monozono Imari.
Takateru comes off as an incredibly kind and gentle person who is always impeccably polite to everyone. Typically mild-mannered, he is also deemed a seemingly flawless person who properly looks after his kouhais. Furthermore, unlike most of the Pivoine members, he is studious (grades usually in the top ranks) and a humble person who doesn't discriminate others based on their families' net worth.
However, according to Imari, this is part of his black-bellied facade.
Despite his relationship with the heroine Reika, he made no appearances in the original You are my Dolce. There are several theories made by fans considering reasons as for why it turned out to be so.
He is quite protective of Reika as shown when he hit Imari after Imari made a joke about him and Reika getting married.
Character theme song is Ravel’s Bolero (ch 48)
He is in the Kyodo club of his school.
Saved Reika from (almost) drowning once. (chapter-7)