Toriel

Toriel had tried to help seal away the Moon Lord's spirit, and in doing so, learned her occupation was a Nurse. After Asriel's death, the former queen had lost her smile and wandered away from the throne, into a sort of getaway house to recover with books and snails gallore. She had watched the six human children come and go with a bad ending. In seeing so, she became overprotective and became the overprotective mother of Frisk. Until Frisk fights Toriel and spares her, then once again, she becomes lonely, realizing what Asgore might do, she tried to chase Frisk. But was too late to save them. Until the second run where she makes it on time. Toriel is still a terrifying icon to the monsters of The Cavegrounds and is still unknown to the others, besides Sans. She doesn' exactly go outside the AU, mainly because she isn't aware that there's a way outside of the AU.