Altertale Gaster is a character in Altertale, in which he takes on the role of Asriel. He is the younger sibling of the skelebros.

Gaster was the first monster after the war to ever meet a human. He takes on the shape of flowey the flower, just like Asriel in the original game.


  • The late prince of the underground, the younger brother of Sans and Papyrus. He was the first monster after the war to meet a human. 
  • Asriel personality prevails over the original Gaster personality.
  • He looks younger than his real age (apparently 10 years old). 
  • In combat, uses bones and "Blue Heart", in addition to the majority of attacks from UT! Asriel.
  • Does not use Gaster Blasters.
  • Can use telekinesis. 
  • When he uses magic, his eyes turn magenta. 
  • His older brothers taught him how to use his powers. 
  • Despite his age, he was very strong, which surprised his brothers and made them proud. 
  • He was sometimes mysterious. 
  • But more often he was occupied being a precious little brother. 
  • He was not originally fond of Sans puns, but they grew on him. 
  • Turns into Omega Flowey on the Neutral Run.
  • Turns into the absolute god of hyperdeath on the True Pacifist Run. 
  • Is Flowey. (has black petals instead of yellow) 
  • In the guise of Flowey, calls Toriel "Floofy Dirtbag". 
  • Has also probably been around for a while, but looks about 10. 
  • Uses wingdings, but can also speak English 
  • Gaster actually had a creepy face of his own. He didn't used to, but since Chara sometimes used theirs to amuse him, Chara wanted to see if Gaster could make one too. At first, the expression was really weak, but one day, Gaster tried again. It was perfect, but it embarrassed Gaster so much that he never wanted to try it again. 

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