My story for the slimes(part of my theories yet to be posted):
Cthulu grew jealous of Anubis's hallow and the jungle, but one day he noticed the slimey stuff(Cthulu's sweat-ish) that came off his body moved on its own, he gave them a purpose:destroy Anubis's creations.(before the corruption)
Decades later, in an underground castle found in the corruption, the shadow clan was formed.
In the shadow clan there were ninjas that could bend shadows and turn into ones, naiads, beings of water corrupted by Cthulu, and the dark ones(cloaked men of the unknown). One day, their leader(a ninja) finished his crown, but right after he put it on he noticed some goo squirming towards him, he picked it up, but it literally grew over his body parts. He eventually bonded with it(like a symbiote from Spider-Man), he gained new powers because he could control the slime but one day, he went... crazy with his power; he absorbed other slimes and growing. Eventually he couldn't control it, the slime's mind overcame his and for some odd reason the other slimes followed him like a leader; no longer following Cthulu