Jackal was an alien defeated by Ultraman King and banished to spend an eternity in a black hole. Having returned, Jackal sent his armies to Earth to uncover any Ultra Warriors that may be hiding in humanoid form there. Jackal's minions resorted to threatening to kill human beings held as hostages in order to force Ultra Warriors to reveal themselves. Just when it seemed all hope was lost, a mysterious warrior wearing a suit of armor that obscured his identity appeared from the heavens...
[Additional info from Anime News Network]