Asriel

Asriel is the final boss of the True Pacifist Route. At New Home's Barrier, Toriel, other main characters, and monsters stop Asgore's encounter. After absorbing the six human SOULs, Flowey ensnares and absorbs the monster SOULs. Flowey then transforms into his original form, Asriel Dreemurr, intending to defeat the protagonist and restart Undertale from the beginning. However, he mistakes the protagonist for the first human.