Gin

Sans, who now prefers to go by Gin, is a 19-year-old skeleton and the formidable Captain of the Queen's Royal Guard in the Underground. Born into harsh circumstances, he was forced to mature quickly due to an absent, alcoholic brother. To survive, he falsified his age and joined the Royal Guard. He is arrogant and cold hearted – well he acts like it, but there is more to him then meets the eye.

Gin is a complex figure, though on the outside he's an unlovable prick who would do anything for a scrap of praise from the queen – on the inside he just wants his brother to care about him, because Sans blames himself for everything. He is rich, owning the largest house in Snowdin, and supports his older brother, Papyrus, who is unable to hold a job due to laziness, and can't even bear to look at Gin anymore (due to what sans has done). Despite his outward brutality, he is insecure, easily manipulated, and believes only in survival in a world where power has replaced love. He is straight and doesn't have a girlfriend. Believes that the royal guard keeps everyone 'safe'. Gin's character is from the Undertale AU FellSwapX, created by xXtha on DeviantArt.

Queen Toriel, hardened by the loss of her son, rules with an iron fist, using the Royal Guard as her enforcers. Gin rapidly ascended the ranks not through valor, but through absolute obedience, even to the most brutal commands. He earned his captaincy after unflinchingly executing dissenters, including Monster Kid. Gin now wears his uniform with a grim sense of duty rather than loyalty. Gin and all of the monsters live underground.