Male protagonist of the series. A relatively introverted high-school boy with high intelligence and an interest in books of all kind. Moved in with his ex-girlfriend after their parents remarried.

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she’s the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That’s right, we’re family now. No matter how much we may have thought we loved each other before, we saw one another’s true colors and realized we weren’t meant for each other. That’s why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.<br>
<br>
(Source: J-Novel Club)

 __Height:__ 5'6"
__Agency:__ I'm Enterprise

He is married to someone from outside the industry since 2011, and two children were born from this relationship. 

[Website](https://shimonohiro.com) | [Blog](https://kimadou.exblog.jp) | [Twitter](https://twitter.com/shimono_kousiki) | [Profile](https://www.imenterprise.jp/profile.php?id=38)

**Non-Anime Roles:**
• Lyney (Genshin Impact)

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she’s the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That’s right, we’re family now. No matter how much we may have thought we loved each other before, we saw one another’s true colors and realized we weren’t meant for each other. That’s why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.
<br><br>
(Source: J-Novel Club)

Mizuto Irido