Why do toi think reds and blacks come up so often in fancharacters?

1. It is a universal truth that red and black look good together.
2. It make a character seem tough but not depressed ou unapproachable (as opposed to, say, all black ou black and purple)
3. The couleurs fit a lot of subcultures, i.e. goth, punk, emo, scene, hip hop, and so on.

Source: my main TD OC wears these colors. C:

It's possible because Black is a color that goes with everything, 'what do I put with this that'll look good? Black.''Nothing goes nicely with this color. Black' and sometimes it's simply that's how they decided their OC was gonna wear a lot of black.
And Red is that kind of color that tells people 'I might snap so stay a sûr, sans danger distance away'