Souls in the back are the characters from ending time octet phase 5

Cage of Abyss by MC-Hooray

Cage of Abyss

Chapter 2: End and Beginning (ignore the ending time octet logo, the image is from before plans a b and c were moved to their own chapter)

Plan A: The Pioneer, The Terminator

Members:

sans (Undertale)

sans (Undertale: The Last Stand)

PAPYRUS (Undertale: Rejuvination Classic)