You're originally a scientist. You wanted to make something knew to help both species, but ended up making this black and white goo. It eventually gets on you and corrupts you're mind. That's your villain story. Now you're a villain and trys to take over the world but hypnotizing anyone with the goo on it. We'll call the goo, Mono. So the SquidBeck Splatoon trys to stop you but you manage to capture one, that being Agent 4. Now the others or at you're base trying to get them back.