Ellis is an incredibly minor character in Baldur's Gate 3. The only evidence of their existence is in a single note in the fishing shack in the Shadow Cursed Lands. The note reads: "Gone fishing. CATCH you later! - Ellis"
While never seen in game, a few things can be deduced about the character given the circumstances surrounding them. Ellis is probably a fisherman, as seen by the note and the fishing shack. Ellis is probably male. While Ellis is becoming more of a unisex name as of late, it is a historically male name. The fate of Ellis is uncertain, however it can be reasoned that he is deceased, either by the Shadow Curse, or the abundance of Kuo Toa in the immediate vicinity of the shack.