Chara

' THIS CONTAINS SPOILERS FOR UNDERTALE. '

Appearance
Chara looks strikingly similar to the protagonist, down to a "similar fashion sense," as said by Asriel Dreemurr, and just like the protagonist, has an ambiguous gender. Both appear to have been around the same age after falling into the Underground. Chara's SOUL is also the same color as the protagonist's, which is indicated by the red SOUL on Chara's coffin.

At the end of the Genocide Route, Chara is seen to be wearing a lime and cream-colored striped shirt (which is an inverted color of the protagonist's shirt) and red-brown pants and shoes. Chara has peach skin and brown hair, rosy cheeks, open brown eyes, and an unsettling smile that contrasts the protagonist's stoic expression.

Personality
While initially cast in a sympathetic light, Asriel admits at the end of the True Pacifist Route that Chara "...wasn't really the greatest person." Asriel states that Chara climbed Mount Ebott for an unhappy reason, and adds that Chara "hated humanity".

At the end of the Genocide Route, Chara behaves in a polite, deliberate manner, thanking the protagonist for guiding them, and teaching them that power was the reason they awoke. They tell them that their determination woke them from death when entering the Underground. However, if the protagonist refuses to destroy the world, Chara becomes frustrated and confused, wonders what the player wants instead, and then finally gives in to the frustration, erasing the world anyway.

Backstory
Idk, help me out here - krys