Lore:

Across the multiverse, things had shaken up quite a bit.

After Ultraman's betrayal during the battle with Destoroyah, the multiversal council had been stripped of their crowns and left to sort out how they'd continue their duties in protecting the network without the enhanced power the crowns gave them.

Gamera and Zone Fighter eventually pieced together that Ultraman was truly Ultraman Dark in disguise, leading them to believe that their original ally was either dead or imprisoned somewhere.

Zone figured out how to access the network and the two of them confronted Ultra Dark in their grand annex. Their crowns reignited and they attacked the dark impostor of their old friend.

The fight was short lived, as Zetton emerged and nearly killed the both of them while his army of Ultra Dark's watched from above, a crown floating above each of their heads.

Zone tried to portal both himself and Gamera out of the annex but a strange magenta portal collapsed beneath the turtle and pulled him into a nightmarish landscape of flesh and sinew.

Gamera fell once more through a magenta portal and landed in a city where an old enemy of his, Zigra, was laying waste unopposed. He'd killed this universe's Gamera, running free without issue.

The turtle let out a mighty roar that shook the ground, his crown pulsating as he charged Zigra. The battle was over in a matter of minutes. Zigra was no match for the crown imbued Gamera.

But how did Gamera even get here? What had brought him across the multiverse in such a vile, terrifying way?

Credit for prompts @flancortes