A Siren In The Skeleton House

Many centuries ago, three races ruled the earth: Monsters, Humans, and Beasts. For eons, the three species coexisted peacefully. However, humans eventually grew fearful of the magic of monsters and beasts and wages war against them. With the help of Mages, the humans won and locked the monsters into multiple mountains with a powerfull spell that would each require seven human souls to break. Beasts went into hiding, some seeking refuge deep in the forests while those with human forms hid in plain sight.

Now, centuries later, it's been ten years since monsters broke the barrier and beasts are still in hiding. One such beast, a megalodon siren by the name of Charcoal, works at a coffee shop and is friends with a lively group of skeletons! He's kicked out by his monsterphobic roommate and after mentioning to Rus and Black that he only has a week to move out, they offer him a place to stay! Charcoal agrees with the promise to pay rent and moves in, but how long can he keep what he is a secret? And why does he never talk about his past?