W. D. Gaster is the current Royal Scientist. He is the only ally that Emily has throughout the game.
He is notably a coward. If Asgore, Alphys, Undyne or Asriel are present, he will run to hide. He is very intelligent, helpful, caring and careful. From being abused by Asgore for failing, he has become a workaholic and an insomniac. He rarely sleeps, as he is afraid Asgore will hurt him. Despite being afraid of almost everyone, during the Genocide Route, he will fight the protagonist, as she has killed his two older brothers. He is suicidal, and the final True Pacifist quest is to find him in True Lab and stop him from committing suicide.
He has white bones and no hair. His right eye is constantly resting, being sealed with a crack, and another crack is underneath his left eye socket. He has several cracks on his face, and holes in the palms of his hands.
He wears a light brown sweater, grey pants and black shoes. He also wears a white labcoat.