Gaster was originally an Epic monster and the only one able to give Gaster Blasters. Sans was later also able to give them, but they became exclusive to him (not counting other generated cards or Artifacts) when Gaster was turned into a Legendary in Beta 46.0. Effect updates and description changes can be seen here. Previous Versions of his Blaster can be found here.
Undertale OST..

Undertale OST...? - Gaster's Theme Extended

Gaster is able to retrigger all Synergy effects you successfully triggered this game. Synergy is an effect also added in Beta 46.0 and became the replacement of Future for his Followers, making Gaster the Ace of a Deck featuring them, similar to how Muffet became the Ace of the also new Arachnid Tribe. However, unlike her, Gaster isn't a Follower himself.

Due to it only triggering Synergy effects and also having Haste, G Follower 1 and Redacted have no impact on this.

Card Skins

Card Skin (Gaster)

Dark Darker

  • Dark Darker (by Moonlightring)
    Card Skin (Gaster) 2

    Very Interesting

  • Very Interesting (by Darky)
    Card Skin (Gaster) 3

    Glitched Gaster

  • Glitched Gaster (by CoreSilence)


  • During testing, Gaster didn't have Haste as it was meant to actually be obtained from Redacted. But this didn't work properly, and it was decided to give him Haste by default.
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