A possible fanfiction could involve Kiryu's memories of Godzilla influencing the RWBY characters. For example, Godzilla's tenacity and will to protect could inspire Ruby and her team. They could learn from Kiryu's combat techniques and use them against the Grimm. And perhaps Kiryu could be repaired and upgraded using RWBY's technology.
The combination of two very different universes. RWBY has its own set of unique characters with various powers and personalities. Godzilla, on the other hand, is a huge, powerful and iconic monster. When you put them together in a fanfic, it creates a whole new dynamic. Writers can explore how the RWBY characters would react to Godzilla's presence, or how Godzilla might interact with the world of RWBY.
One main theme is the clash of different powers. Godzilla has his atomic - based powers which are so different from the semblances and combat skills in RWBY. So, the fanfic often explores how these different power systems interact.
One interesting 'godzilla and rwby fanfic' could be 'Godzilla in Remnant'. In this fanfic, Godzilla somehow ends up in the world of RWBY. It creates a really unique dynamic as the characters from RWBY have to deal with this giant, otherworldly creature. The story plays with the idea of how RWBY's combat skills and semblances would fare against Godzilla's might.
Ruby would find it amazing. She'd be so into the huge scale of the Godzilla stories and would probably try to incorporate some of the epicness into her own fighting style. Weiss would be a bit of a snob about it at first, but then she'd get into the complex relationships between the characters in the fanfiction. Blake would like the deeper meanings and the exploration of power and fear. Yang would be all about the action and would be like 'Go Godzilla!' the whole time.
Yang would be a likely character. She's bold and not one to back down from a challenge. She might see Godzilla as a huge opponent to test her strength against. Maybe she'd start off trying to punch it, only to realize that brute force alone won't work and then have to figure out a more strategic way to interact with it.
Yang would probably be the most vocal about it. If there were epic fight scenes in the Godzilla fanfiction, she'd be hyped up. She might even joke about how Godzilla's moves could be used in her own fighting style. Weiss, on the other hand, might be a bit more critical at first. But as she read more, she could start to appreciate the creativity behind the fanfiction, especially if it had elements of strategy and magic - like in her own experiences in Remnant.
One idea could be Godzilla emerging in the world of RWBY and the Huntsmen and Huntresses having to figure out how to deal with it. Maybe they initially mistake it for a new type of Grimm.
Kiryu could be a lost relic from an ancient civilization in the RWBY world. It has been dormant for ages until the RWBY characters accidentally awaken it. Since it has Godzilla's essence, it has incredible power that could tip the balance in the fight against the forces of evil in RWBY.
Well, I'm not sure about specific 'rwby godzilla fanfic' titles off the top of my head. But you could try searching on Reddit. There are often communities dedicated to fanfiction where people might share and discuss their favorite 'rwby godzilla' crossovers. You might find some hidden gems through that.