XGaster Teacher

Everything was fine in the past. He had a good wife and three sons. The eldest, Chara, is human like his mother, the middle son is named Cross and is a skeleton like Gaster. Papyrus was the youngest in the family and he is also a skeleton.
Later, Gaster's wife died, and he sank into a temporary depression. He went from being a kind father to being strict, serious, and cold. He began mistreating his son, Chara. Chara was 14 at the time. Unable to bear his temper, Chara ran away. Later, to numb the pain, he went to school to teach other students discipline and punctuality while working with children.

Now he also has two son skeletons. Cross is now 12 years old. He is quiet, calm, and kind. His eyeballs are black like Gaster's. The right iris is red and the left is white. The pupils are black. He likes to read books and, among other foods, he loves marmalade, chocolate, and tacos.
Papyrus is sociable, active, and sweet. Papyrus is 10 years old. His eyeballs are also black. Both irises are white with black pupils. Papyrus loves cookies with milk and marshmallows.
Chara had white hair and his eyes were red. By nature, he was decisive, argumentative and vindictive.
After Chara escaped, Cross wears a yellow heart pendant around his neck that Chara left him, in memory of his older brother. In front of his father, he takes it off and puts it in his pocket.

Cross and Papyrus attend the same school where XGaster works.

XGaster is a skeleton and an Algebra and Physics teacher. He is 1.95 meters tall.
He loves to drink strong black coffee and constantly write in a notebook.
He doesn't like it when someone is late for his lessons or when they don't listen to him.
A skeletal body and its skeletal shell. There is no hair. On the left side of the eye there is a thin black stripe down, and on the right eye there is a similar thin black stripe on top. His eye sockets are black, the irises of both eyes are purple, and the pupils are black. In each of his skeletal palms there is one large round hole.
He wears a white sweater. He has a dark purple turtleneck over it. It covers the sweater except for the neck and sleeves that reach just below the elbow, leaving the sweater visible. He wears a floor-length trench coat over it. Around his waist is a dark purple belt with a white X. The sleeves on his XGaster trench coat are white and tucked into his arm, which looks good.
His pants are dark purple, like his boots. He wears square glasses. There is a yellow heart pendant in his pocket.
By nature he is strict, serious, cold, important and seemingly cruel.