This is Chara She offen wear Green sweater and has brown hair and wears a heart locket, Well its seems be like Chara but she from another AU called Underswap its where all the characters are swapped roles and personalities so its far different then Undertale, She Is a Human who fell in to the underground like you, She is very Kind hearted and Put others before herself she also is Really sweet she like to be around others and hates being by herself, She has a toy knife to defend herself,