Ink!Papyrus (a.k.a. Paint!Papyrus) is a brother of Ink!Sans.
His personality is unknown, but he would most likely be mature, responsible, enthusiastic, and of course, creative.
His appearance suggests an adventurous yet laid back attitude hence the satchel (always ready for action) and the fact that he has multiple accessories that fit loosely (not caring too much about it fitting perfectly).
He was literally MADE to be his brother and another character in Inktale.
It is unknown if he as interacted with other AUs such as Errortale (since he has no story and is not canon.)
Is his friend.