errorRIZE will be a new character who will (perhaps) be part of Matias' Adventure! (A FNaF World of WTMR) he is, special...
He is the BETA sprite of Matias that was deleted after the current version arrived, but this one was reconstructed with fragments of code, creating this aberration

He would be part of my interpretation of the ending of the clocks of Classic FNAF World

It's simple, after talking with the guide of your adventure, you will be able to find it in a glitch part of the first world, when falling into that glitch, you would be transported to his world that he created with just code.

Matias would FALL ALONE to this place, leaving the rest of the team without their leader. Upon arriving, he meets errorRIZE who offers him a deal: if he helps him rebuild and be able to be part of this game, he will leave him alone. For that, you must visit him with the objective of creating code and sprites to rebuild him. The catch is that errorRIZE needs the code and sprite of MATIAS in order to restore himself.

By obtaining everything before the final battle, errorRIZE would congratulate him, but would tell him the truth, he needs HIM, to finish Matias once and for all to steal his code and finally be free from this place.

Obviously Matias would refuse and errorRIZE will do it by force, with a 1v1 fight, here you will have to dodge his attacks through certain interactive actions he will take.

It's an intense fight, since he will be able to heal if you don't do enough DPS to him.

After defeating him, he will leave you alone, and he will give you a piece of code to get 2 extra worlds, one will be a collab with another FNAF fangame that I am thinking about which one it will be, and a world where you can farm experience for the animatronics and tokens to buy bytes, armors, etc...

And in fact, he will become an ally, and he will become a playable character, very strong, who will help against the final battle