Deny the obvious. Uphold the inane.
The Anomalies are not Gods, they are two of the wizards who created the barrier.
Several things about the two, like Pacifist attempting to SAVE Genocide and she "forsaking" her "old name" implies they were once at least semi-normal people. This, combined with their Battle Aura makes me believe that they were part of the group that made the barrier, if their colors are any indication Genocide was the Wizard of Determination and Pacifist the Wizard of Integrity. An alternate, they are two of the fallen humans...
...who somehow ended up in the Void and became godlike Humanoid Abominations. Not my idea, but it's one of the theories in "Be Prepared" video comments.