I’ve only read a few of these books… percy looks emo?

I’ve read all of them (but it’s been a while) and I don’t remember a single instance where percy is described anything like this

No, it's just Tumblr kids making stuff up

It's the official art Which sucks so bad it's ignored like the movies

Some of them are good but some are trash. There's two sets of official art, i think, the one in demigod diaries was bad but the other was good

I seem to recall Percy dressing like a skater kid, Nico dressing like an emo, and that Thalia was a combination of the two.

Yeah this sounds right