This is the owner of Pure and Impure writing- do not edit this page unless you have my permission.
Pure is an Asriel that was created after lore (1) happened and thus, he was born as Snowy. Then, lore happened again (2) and he became Error!Asriel. But, then Snowy split into two halves: the Good and Evil. Pure is the good. Pure is known in roleplay as a white-furred Asriel with a blue shirt and a scarf if outside in Snowdin or other cold places. He currently takes care of Impure, a dog. More on that later. He currently has the more magic out of the Snowy Twins.
Follow the lore above, but instead focus on the Evil half. This is the evil. Though, Impure has learnt to be kind and all that mushy friendship stuff, and not be evil. He's also a white-furred dog- did I mention that? More specifically, a species of Annoying Dog. Impure has little magic, due to being a dog, and cannot speak. He can understand you, though.
They live in a dirt room, with a trapdoor to get inside and a ladder to climb. There is a fire and plants growing inside, plus an bucket of ice (magically kept icy using Pure's magic) with raw meat/veggies in it.
(1) Undertale RP Lore (unarchived) (2) The Error Arc