>>280222154
Yeah, Iris is literally his dream girl, the heorine he wanted from the start and was complaining out loud he didn't get. Reminder his definining characteristic before he got isekai'd is his imouto fetish, he literally tried to get his parents divorced so they would remarry and give him an imouto.
That said, his close relationship with Megumin made up for any box she didn't tick, meaning Kazuma has two girls who he feels that special way towards.

Iris is 13, which is prime. She's 139 cm tall, which is also prime.
Neither is true of Megumeme.