BarnOwlMan

My KillerDust take

After multiple runs, on one specific Genocide run, the Player notices that somehow someone else has already started killing Monsters, with survivors saying that it was another human. When the Player reached the throne room, they finally saw the one responsible, aka Executor/Executioner, a being similair to the Player (in-universe) with their only goal being to "put the world out of its misery".

They seem to be connected to "HIM".

They're very similair to Flowey.

My DustKiller take

"Murderer" is the result of the Player doing multiple Genocide Routes, in turn "degrading" the world from the multiple erasures and recreations of the world and the Player growing bored. This causes a certain Doctor to implant your SOUL into Sans to "keep things interesting". Combined with the "changed" world results into an experience that intrigues the Player.

Sans isn't concious during all this.

"Murderer" is right handed because of the Player.

His movements are very puppet like.

JestilorG

Poppy the Sleepy Gift Giver marionette

(Puppet redesign)

Clown D. Vil

Devyne

By Rattel_M_Bones on Twitter