Trey Theory: Trey most likely started out as a human, one with black hair (as shown in "Treyola explains climate change"). He also has been shown to have Pica, or the tendency to eat inedible things (as shown in several of his fighting projects). Treyola (the account not the character) had a character named Emerald, his first original character. Though Trey as a character has gone through many different looks and styles, I believe that Emerald was not Treyola. I believe that Trey and Emerald are two completely separate people. So I believe that Trey had came across Emerald, and decided to eat him for no reason (or from pica), which ultimately killed Emerald. And since emeralds are obviously indigestible, Emerald's body sort of just stayed in Trey (as shown in cs3676602's ,Treys school account's, project "Treyola vs. Error Cat (UNFLINISHED)"). Emerald, however, may have possessed powers that he never showed, and Trey had gained these power after eating him in a manner such as the master emerald, along with getting green hair. However, this isn't the end for Emerald. The project "Emerald Demon" features a lemon demon look alike of Emerald. Though it could simply be a fun concept, I believe that this is Emeralds aftermath. After he was eaten, he had became a demon and is seeking revenge on Trey. However, the incorporation of the song "Not a Monster", shows that Trey is most likely his only goal, and that he won't harm anyone else unless they are in his way. We don't know if he will be able to get revenge till the plot is furthered, but that is my Treyola theory.
^ Read the Instructions above for theory ^ -Thank you @Burrito_anim, for inspiration of the art style. -Thank you @Treyola_Reborn, for obvious reasons. Links: -Treyola Explains climate change: https://scratch.mit.edu/projects/364429055/ -Emerald's first appearance: -Treyola vs. Error Cat (UNFLINISHED): -Example of Trey's Pica: -Emerald Demon: