Appearance: tall skeleton, has holes in his hands, black clothing, half blind because of a crack in his skull Personality: polite, dedicated scientist, ominous, caring father, mysterious, intelligent, tough love Gender: male Children: Sans and Papyrus Gaster was the royal scientist in the core until he failed an experiment and he vanished because he was in a tragic accident involving the failed experiment. Everyone thought he died, and he was the hope of freeing the monsters from the underground. Before all this he was a single father and Sans and Papyrus was his everything and he would do anything for them.

Appearance: really short skeleton, blue hoodie, white shirt, pink slippers Personality: lazy, makes lots of dad jokes, chill, playful prankster, can become serious when pushed or mad Gender: male Caretaker: Gaster (was) He is the older brother of Papyrus, despite their height difference. He cares for his brother deeply. He made sure he was safe after Gaster had disappeared.

Appearance: tall skeleton (slightly taller than gaster), white chestplate, bright red gloves, oversized bright red boots, red scarf Personality: silly, optimistic, confident, oblivious, cooks spaghetti, puzzle crafter Gender: male Caretaker: Gaster (was) He is younger than his brother Sans, despite their height difference. He cares for his brother deeply, despite him being lazy and making lots of dad jokes (which he hates.) But he doesnt care and likes his brother either way. He is also a royal guard, and his goal is to capture a human.