Overlord Momus (InstanceTopic, 8)
From Compile Worlds
Overlord Momus is an idea created by Arfoire in order to spread fear amongst the people and thus grant Arfoire more power.
It seems that Momus did not actually exist as a monster in the original 2010 game (only as an idea), but does in the 2013 remake Hyperdimension Neptunia Re;birth1; additionally, the Momus you see in the remake is the same form as a form that Arfoire herself takes in the 2011 game Neptunia mk2.