An inversion of the Returning Big Bad Trope, here the main villain tries to come back but fails and falls to the wayside of history.

Alien Empera is the primary antagonist of Ultraman Mebius (2006), though he was originally first mentioned in Ultraman Taro (1973, and is considered one of the franchise's most powerful villains.

30,000 years before the original Ultraman series, Empera invaded the Land of Light with an army of Kaiju & Aliens. The Ultimate War, as it came to be known, ended when Empera lost to Father of Ultra in a dual. 

Badly wounded, Empera fled and spent years regaining his strength and rebuild his forces.

He would eventually set his sights on earth but his forces were defeated and Empera himself would eventually fall to the combined power of the Ultras and Humanity. 

Empera would then attempt to ressurect himself in  Ultraman Mebius Side Story: Ghost Rebirth, using the warrior Mechazam as his vessel, however Mechazam was destroyed before the resurrection could begin.

This was the true end for Empera and he has never reappeared proper in the series since outside of some stage shows and one dummy version of him created by another antagonist. He's pretty much be confined to flashbacks of the Ultimate War.

Even in the Ultra Galaxy Absolute series, which saw many old antagonists ressurected, Empera wasn't amoungst them despite having usable suit.

(InvertedTrope) The Big Bad tries to come back, but never dose.