The Dark Ruler that invaded the Land of Light 30,000 years ago and caused the Great Ultra War.
It controls many kaijus and aliens, including the Four Heavenly Kings of Darkness.
It boasts incredible power, with weapons that can disintegrate the flesh of Ultras, like the Rezolium Beam and the Heavy Energy Wave

When the Four Heavenly Kings of Darkness were defeated, he descended upon Earth with its army of Inpelaizers.
It declared war on humanity, then summoned thunderclouds that plunged Earth into darkness.
Using telekinesis, it turned the surrounding area into a sea of fire. It defeated the Space Swordsman who stood in its way using a Heavy Energy Wave, provoking Ryu to transform into Ultraman Hikari and join Ultraman Mebius in the fight.
It defeated Mebius with the Rezolium Beam, but Mebius merged with his CREW GUYS friends to be revived as Ultraman Mebius Phoenix Brave.
This new form was unaffected by the Rezolium Beam, so was able to turn the fight around. Finally, Empera was struck by the Mebium Phoenix and eviscerated in a flash of light.