Well, 'Gamera' movies are also quite good in the kaiju science fiction genre. Gamera is a giant turtle - like kaiju that has its own series of films. It has different abilities compared to Godzilla, like being able to fly. 'Cloverfield' is also a notable entry. It shows a kaiju - like creature attacking New York City in a found - footage style, which gives it a very immersive and unique feel.
Kaiju novels often portray kaiju as gigantic and powerful beings. They are usually depicted as forces of nature that are difficult to control or defeat. For example, in 'Godzilla' novels, Godzilla is shown as a nearly indestructible creature with its atomic breath and massive size.
One popular 'kaiju x kaiju fanfic' story could be about Godzilla and Mothra forming an alliance in a unique way. Maybe they team up against a new, more powerful enemy that threatens their world.
How about a Kaiju that can split into multiple smaller versions of itself? This would be a strategic advantage as the Jaegers would then have to deal with several threats at once. Each smaller Kaiju could have a different ability, such as one being able to spit acid and another being extremely fast.
To write a compelling Kaiju character, start by giving it a distinct appearance. Describe its size, color, and any unique features like spikes or tentacles. For example, a Kaiju with a massive, spiked shell on its back is immediately more interesting.