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.
They'd be very meta, like Flowey.











