Various info:
They suffer from chronic insomnia.
They live in a run-down building with a bunch of other people that they're friends with
They like to play video games, go to the movies, and read fanfiction. They sometimes watch game streamers.
Their voice is androgynous.
They know a small amount of English, enough for some simple sentences, but main language is Tratac. Known words/phrases: "fuck you," "where is the bathroom," "thank you," "That's shit". Accent sounds a bit like a Mexican accent mixed with Eastern European and Middle Eastern one. "fock you," "weyar iss thee bathroom," "thenk you," "That's sheit."
They got their nickname from the last syllable of their name and the fact that they are often leaning on something because they are very tired. Obviously, "lean" is another English word they know!

Mote Crester info:
They experience no detrimental effects from aging; biologically immortal.
They can live off of eating anything that's sufficiently foodlike.
They don't produce waste, due to magical digestive tracts.
They almost never get sicker than a runny nose and a mild cough. Diseases that are deadly to other species either have no effect or are mostly harmless.
They don't get cancer, and can grow back any missing parts, although it may be very slow.
Prone to weird disorders, such as Leaner's sleep conditions. Could also be things like sneezing when someone teleports nearby, or being easily fixated on things that most people don't notice or care about.
Covered in fuzz! It can poof out a bit if air-dried.
They never loses sensitivity to physical stimuli.
They never chafe.
They have do not have an estrus cycle.
They have distant Toon ancestry of some form.

More info to come, maybe.