Toriel

Toriel is a very kind and motherly monster who truly cares about the player and their well-being. She also has a harsh personality, as can be seen in her refusal to allow the player to leave the ruins and in her cold relationship with Asgore.

Its appearance is that of an anthropomorphic goat with long eyelashes and a dark red iris. She wears a large purple/blue dress that has the Delta Rune etched on the chest. This can also be seen in the True Pacifist Route menu or in your own home with reading glasses.

Before the events of the video game, Toriel was queen of the Underground, wife of King Asgore, and biological mother of Asriel.

One day, a human falls into the Underground. Toriel's son, Asriel, takes him with her and is treated as part of her family. Some time later, the human becomes seriously ill. The next day, he dies. Asriel uses the human's soul to cross the barrier, entering a nearby town, and places the human's body on a plain of Golden Flowers that grew in the center of the town. The humans of the village thought that Asriel had killed the infant and attacked him with everything they had. Asriel returns injured to the Underground, where he eventually collapses in the throne garden and dies crumbling to dust on the flowers.

In a fit of rage and sadness for having lost two children in one day, Asgore declares war on the humans, but Toriel does not accept this behavior and chooses to retreat towards The Ruins.