Mother Toriel from the Dulentear! AU is the Queen of Paradise, one of the eight realms in the world of Dulentear. She's more like a morally-questionable goddess compared to the other 7 Deltarulers being tyrannical dictators.
The strange black markings across her neck are unhealed scars from when The Knight decapitated her and is also why her goat ears are tied with ribbon.
(More Lore Below!)
Mother Toriel was one of the very first Deltarulers in the world of Dulentear, along with her ex-husband King Asgore. During their eventual split due to a disagreement on how or who should run things, Mother Toriel took her people to a land of clear rivers, sweet fruits and green trees which she named ' Paradise ' while King Asgore, heartbroken and wishing for solitude, fled to the comforting silence of a mountains cavern known as Ebbots Falls. (Toriel took Asgores subjects in the divorce 😭)
But don't let the name of the place fool you, Paradise is less like a fun vacation spot and more of a Midsommar-esque cult where everybody worships an oddly familiar golden flower.
During The Knight of Wrath where a mysterious pitch-black figure clad in armor and antlers had arrived, striking each and every Deltaruler across the seven worlds, Mother Toriel was the last to face The Knights blade. It didn't came as surprise to her, she had been meditating under a tree this whole time.
After The Knight had left, the tree was no longer standing... And so was her head.
It was luckily re-attached but like many Deltarulers, the wound never fully healed! This event made Toriel even more controlling of her people and she forbids her paradisians from leaving their home...