Overseers are beings created by gods to watch over their worlds to make sure they are stable. The bodies of overseers contain a core with a shell made of energy that keeps them alive. Overseers are incapable of shapeshifting like chimera or other gods, so if an overseer desires any physical changes they must consult a god.
Being bound to a god has it's perks! An overseer can communicate with a god at any time, and use weak magic associated with that god.
Overseers are like robots, they have no need to eat or sleep, and many have preprogrammed personalities that stay the same as long as their god keeps it.
If a god were to die, then all the overseers bound to that god would have to be reassigned to a new god, as overseers get their energy from their god.
No two gods create their overseers the same; one god may prefer making plain overseers with normal names, while another may like going full maximalist and make eyebleeding sparkledog overseers with mile long names.
It's not unheard of for gods to gift overseers to each other, with a common practice being for the gifter to try to replicate the style of the giftee.
An overseer lacks internal organs, the only thing in their body being their gem-like core. A core is far from fragile, but overseers typically keep it within their body to prevent it from being stolen, only taking it out at the command of their god.