Perseus

A companion to Aries, but far less outspoken than his mentor. Cursed with a paralyzing stare and monstrous appearance from his constellation's prior lineage, Perseus is prone to hiding himself from others. He may be named after the famed monster killer, but longs for a truly heroic path instead.

Though he can't actually turn anyone to stone with his gaze, his aversion to eye contact is a byproduct of others fearing that he could. If caught off guard or near someone who has never seen him before, he will specifically hide his eyes if he can't hide the rest of himself in that moment. He'll then warn them not to look at him, assuming they will scream and run away if they did. Cassie was one of the first to not do this, pointing out her familiarity with "strange eyes" and finding his to be quite pretty, actually!

Because of his reclusive tendencies, getting Percy to socialize is quite the task at first. Even after he gains friends, some of that awkwardness remains, but most find it charming more than anything. He doesn't understand idioms or slang very well, thus confusing him when taking the phrase literally. For example, if you said "I dig it", he would tilt his head and ask "Don't you need a shovel for that?"

His prowess in combat is partly from training with Aries, and partly out of necessity for his own survival. Despite his ability to think and speak like any other sapient being on the Astral Plane, many still considered him to be a monster like Cetus or Hydra, and thus any particularly zealous "hero" would try to hunt him down. Percy himself tried to be the hero he always wanted to be, someone who kept others safe and protected during an actual monster attack, but was ultimately betrayed. He lost part of his right horn from an axe swing intended for his neck, as the wielder assumed that Perseus was the monster that was attacking instead.

After that, Perseus gave up on his desires and leaned into his monsterhood as much as possible to ward everyone off for good, becoming a sort of "urban legend" lurking around Aries's arena. It wasn't until the ram defeated him in battle and learned of his plight that Aries decided to take Percy under his wing and train him as his own.