Alioth
Alioth , the Supreme Time Being
Alioth is a semi-incorporeal transtemporal being. During the Forever War (a war between timetravellers, primarily multiversal variants of Nate Richards), He Who Remains harnessed Alioth to use as a weapon.
After He Who Remains ended the war, Alioth was imprisoned in The Void, where it acts as the guardian, preventing the inhabitants from leaving, and protecting the Citadel at the End of Time.