His nickname is "Nine". It's canonically ketchup. And the Assist Phases begin! The Shifted Realities Pack contains the first half of Act 5, having Phases 29-40! NOTE: Chara is canonically good in this AU, and Gaster's true form is a fusion of Mystery Man, REDACTED, and the Gaster Followers.
Vector by me. Phase names: Phase 29 - MEGALOGLAMOUR (Ft. StoryShift Chara) Phase 30 - ANTIPATHETIC (Ft. Angry!MT!Negatale!Sans) Phase 31 - EXECUTION (Ft. Sonic.EXE) Phase 32 - GRANDOVANIA (Ft. Canon!FellFell) Phase 33 - MELUNACY (Ft. Last Breath Inc. Phase 33) Phase 34 - Red Megalovania (Ft. Dust!Sans) Phase 35 - Octagonal Prism Phase 36 - VEXATION (Ft. Fell!Sans) Phase 37 - Dancin’ On The Deadline (Ft. FellSwapEmerald!Papyrus) Phase 38 - BLACKED OUT (Ft. Striker) (He’ll heal Sans to normal with a Max Potion) Phase 39 - ANIMUS (Ft. Painted!Jaiden) Phase 40 - NO MORE JOKES (Ft. SwapSwap!Sans)