>>137894187I'd prefer the GOTU origin for Gamera being an altlantean creation to deal with Gyaos. Have the movie start focus on humans finding this cool lost civilization with wondrous sights and strange technology, and then they accidentally awaken a dormant egg of a Gyaos that an ancient scientist hid away. It pops up, so Gamera wakes up and is on the move, leading to a conflict with Godzilla who senses another Kaiju so he needs to assert his stance. Gamera, in contrast, wouldn't really want to fight Godzilla all that much, seeing him as a natural balance, but when Godzilla's desire to prove himself the alpha prevents Gamera from killing Gyaos, it becomes a conflict. Gyaos, unlike Gamera, would pretend to accept Godzilla as the Alpha, meaning Gamera's constant attempts to kill him would only lead to him getting Zilla'd and stopped. It's essentially a long battle where Gamera is constantly beaten, but he strangely never stops. No matter how badly Godzilla takes him down, he gets right back up and keeps trying to stop Gyaos. I think it's important Gamera technically loses, but never quits, because Godzilla is only used to yield or death. It offers a scenario where Godzilla can't manage to kill him, but he won't stop either.
By the end, it's revealed Gyaos has created an entire swarm, enough to wipe out the entire planet, and Godzilla realizes he fucked up and has put the entirety of nature in danger. Final battle is an all out war with the military, Godzilla, Gamera and maybe some other Titans cameoing struggling against this massive horde, and even though he's badly wounded it's ultimately Gamera who saves the day and stops them after Godzilla is overwhelmed. Movie ends with Gamera going back to rest, he's won his fight, and Godzilla accepting it.
Character development for Godzilla, a for sure answer of who wins so nobody complains about fencesitting, but ultimately highlighting Gamera's heroic underdog nature.