dark matter dont necessarily need sleep-at the very least, they can go a long time without it
however, sleeping does actually help stronger dark matter (like demys) heal themselves/repair their body faster, so dark matter like him do have a sleeping schedule.
which is, for demys, sleeping whenever he feels necessary, aka every few weeks lmao
when he does sleep tho, he's just out like a log

also do i draw demys too much