Papyrus is the Caretaker of the Ruins and formerly one of the rulers of the Underground. He saves the protagonist from Flowey/Napstablook in this case in the beginning of the game throwing a magical bone at him. Papyrus is in the role of Toriel.
Papyrus wears a robe similar in nature to Toriel's, but with a protruding Delta Rune chestpiece and slits at the waist. He wears white pants underneath.
Papyrus keeps his goofy and egocentric personality from Undertale, but in a slightly more cautious and reserved manner.
Papyrus met Chara one night when Chara, in a suicidal mindset, made their way to the Ruins door. They had intended to take their own life, but in their hesitation, they were overheard by Papyrus. Though at first Chara was quiet, the two soon began to speak to one another, Papyrus providing support to Chara and strengthening their resolve to protect their family.
Papyrus' brother. It can be assumed that the two were very close, but after the deaths of Mettacrit and Napstablook, Papyrus left to the Ruins in order to spread their ashes and wound up staying there to watch out for any fallen humans. Papyrus would like to believe that Sans would do the right thing, but as time has passed, he's grown wary that Sans would and has killed the previous humans. However, unlike canon Toriel, he does not begrudge his brother and wants to forgive him.