Mitsumune
Online Handle: Mitsumune (alias used on various websites)
Mitsumune's probably best known for being kind of socially awkward, especially around girls. He's openly admitted he's "quick to fall in love," which tracks with how he comes across in most situations. He's got a strong moral compass and doesn't hide his ideals—he'll speak up about what he thinks is right.
As for his age, it's never explicitly stated, but he's clearly in cram school, which puts him somewhere in his mid-to-late teens or early twenties. Not a kid, but not fully grown either.
Content compiled by AnimeList.moe from publicly available sources.