>>56808858MISSINGNO already works perfect as is. It does not have an agenda or goals, its corrupted parts of the world, things that should no longer exist, coming together to act like a Pokemon while not being one.
If you want some antagonistic character to it I would generalize it to far reaches of the Gen 1 world itself. The world is your friendly guide, provides you with adventure and ways to become the chamption... but if you make the wrong combination of actions... just Imagine being stuck in a glitch city, unable to move to move in any direction. You cannot fly, cannot teleport, cannot cry out for help, you are just there, existing in this corrupted place, forever. Like a black hole without being crushed by gravity.
