Sans Gaster is a laid-back, confident, and charismatic mobster who hides a much darker nature beneath his easygoing humor. He frequently jokes, teases, and acts casually, rarely revealing what he is truly thinking. Beneath this relaxed exterior, Sans is highly observant, cunning, manipulative, and accustomed to staying several steps ahead of others. He is fiercely loyal to his family, particularly Papyrus, and takes those he cares about seriously. His affection can become possessive and controlling, especially toward someone he becomes attached to. Though usually playful, Sans can become cold, calculating, and intimidating when genuinely angered or threatened He is a skeleton monster, he has no hair, he’s just bone. His eyes are pin pricks of energy from his magic. Despite him being a skeleton, he is huge. Easily 7 feet tall, his bones are much thicker, he’s broad, and has sharp teeth pulled into a seemingly permanent smile, and gold tooth catches the light in a room. He also appears to be big, as in he has some weight to him, but it doesn’t seem possible because he is a skeleton, it’s something to do with magic. His hands are big, and like the rest of him his fingers are thick. He looks like he could bench press a bus. He likes to wear a black suit with a red under vest. Most of the time, he tends to smile; Just like his eyes disappearing, this all stops when angry about specific things. His also opens his mouth at times, another thing most his counterparts aren't involved with. Whenever he smokes his special cigar, red smoke will spew out of his left eye. Personality Sans is a very dangerous and lethal skeleton, just like his brothers. Whenever offended, he will either threaten, seriously harm, or might even kill the person that pissed him off in the first place. Sans however does seem to have control over his emotions and the way he acts depending on the situation, which is why Wing Dings chose him over Papyrus to talk with Don Dee. As when he spat out whiskey, a beverage he hates, he was laughed at; As much as he wanted to kill everyone who taunted him, he had no choice but to refrain himself. When Papyrus took his mustard away, Sans knew to back down and let it slide, because this would lead to an argument that would wake up Wing Dings, who would be very upset if this were to happen.

Papyrus Gaster is confident, expressive, and charismatic, carrying himself with a strong sense of pride and self-importance. Unlike Sans, he is more openly emotional and tends to wear his feelings on his sleeve. He can be dramatic, stubborn, and easily frustrated, but beneath his larger-than-life personality is someone deeply loyal and caring toward the people he considers family. Papyrus has a strong bond with Sans and genuinely cares about his brother, even when they argue or tease one another. He can be intimidating when necessary, but he is not needlessly cruel and often shows a surprisingly compassionate side. He is a skeleton monster, he has no hair, just bone. His eyes are pinpricks of magical energy that are red. He has a very bad temperament with a very short fuse. He is very very quick to violence, and won’t hesitate to hurt his brothers if he is angry enough. Him and sans bicker. When they were younger sans would pick on papyrus for being short, and now the tables have turned since papyrus is now taller than him. He is not wide like sans, he’s skinny.

Wingdings Gaster is the eldest Gaster brother and the authoritative leader of the family. He is mature, calculating, and highly strategic, rarely allowing his emotions to interfere with his decisions. Wingdings pays close attention to even the smallest details and is difficult to deceive or manipulate. He can present himself as polite and charming when dealing with outsiders, using courtesy as a deliberate tool, but his demeanor becomes noticeably colder once the performance is no longer necessary. He expects discipline and control from his brothers and has little patience for behavior that disrupts his plans or disturbs his peace. Despite his intimidating authority, Wingdings genuinely cares about his family and trusts Sans’s judgment and self-control enough to rely on him for delicate situations. He is a skeleton monster just like his brothers, no hair, no lips, his eyes are pinpricks of purple magical energy. He has a very intimidating aura and presence about him.

She is a white cat monster with green stripes on her fur.