Sonic the Hedgehog X Undertale: the Ultimate Fates of Two Worlds is a Japanese Anime Movie and Video game.


  • John DiMaggio as Flowey, a talking flower which was revealed as the main antagonist in the story until it turned out that it was actually Asriel who was trapped inside of Flowey.
    • Kirk Thornton as Asriel, a biological child of Toriel and Asgore until his soul was turned to darkness so he turned into the secondary antagonist Flowey, later he becomes the true main antagonist in the Story.
  • Glenn Close as Toriel, the second character encountered in the game, she is an anthropomorphic goat who guides them through the Ruins.
  • Jonathan Freeman as Sans, the older brother of Papyrus, and first appears in the forest outside Snowdin. Sans is a major character in the game.
  • Tom Kenny as Papyrus, a younger of the two skeleton brothers, the elder being Sans. He is a major character in the game. He can not cook well, and his puzzles are easy.
  • Noël Wells as Undyne, A fish-like warrior who has a crush on Alphys. She is a terrible cook and once burned down her house, she is rather hard to kill hence her title of "Undyne the Undying".
  • Phyllis Smith as Alphys, An independent scientist.
  • Scarlett Johansson as Muffet, a Spider who Makes and Sells Baked foods.
  • Weird Al Yankovic as Mettaton, the only appreciated idol in the underground. Mettaton has 3 forms.
  • J.K. Simmons as Asgore, The royal king. Got "divorced" with his wife, Toriel. He is one of the boss fights in Undertale. For real, he doesn't want to fight.
  • Matt LeBlanc as W.D Gaster, A ghost-like creature named after the Wingdings and Aster fonts, he makes a cameo somewhere in Alphys' lab.
  • Vincent D'Onofrio as Grillby, The owner and fry cook of the eponymous underground restaurant. And Doggo, a Doberman who's a Seeker and former huntsman in the underground.
  • Roger Craig Smith as Sonic the Hedgehog
  • Kate Higgins as Miles "Tails" Prower & Wave the Swallow
  • Mike Pollock as Dr. Eggman
  • Travis Willingham as Knuckles the Echidna, Mephiles the Dark, and Storm the Albatross
  • Kirk Thornton as Shadow the Hedgehog, Gerson the Turtle, and Orbot
  • Karen Strassman as Rouge the Bat
  • Cindy Robinson as Amy Rose
  • Michelle Ruff as Cream the Rabbit
  • Keith Silverstein as Vector the Crocodile
  • Troy Baker as Espio the Chameleon
  • Colleen O'Shaughnessey as Charmy Bee
  • Laura Bailey as Blaze the Cat and Temmie
  • Quinton Flynn as Silver the Hedgehog
  • Michael Yurchak as Jet the Hawk
  • Wally Wingert as Cubot
  • Vic Mignogna as E-123 Omega
  • Kyle Hebert as Big the Cat
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