Rei Tsukumo is basically a puppet master who likes to work from the shadows—or at least, he wants you to think he does. He's got this whole calculated vibe going on, partly because he genuinely doesn't want people feeling sorry for him. So instead of just being straightforward, he throws everything into this cryptic, mastermind-like persona, complete with all the mysterious dialogue you'd expect. It's a cover-up, really—a way to hide the parts of himself he thinks are uncool or weak.
That said, he's got a pretty healthy ego. He'll straight-up tell you he'd be the perfect pretend boyfriend for Nanako Watase, which tells you something about his confidence level. Whether that confidence is justified or just another layer of the act is half the fun of his character.
Content compiled by AnimeList.moe from publicly available sources.
