2 Angilas Another underappreciated foe. He'd gone 30 years without a starring role until Final Wars. For Godzilla's first foe, and closest ally, that's unbelievable. Needs a legendary update.
3 Varan Starting to notice a trend here? Legendary Godzilla should be everything that the Heisei and Millennium series weren't, that includes spamming the same old opponents. Some of these kaiju were used so sparingly that most cinemagoers might actually think they're original creations. No need to create a new undoubtedly American kaiju when there are so many awesome Japanese ones that have barely been used. Give us Varan!
4 Destroyer A more recent enemy, and actually quite popular. So why would I buck my established trend in favor of a more mainstream pick? Hollywood blockbuster CG fx could finally do this hulking demon justice in a way that his initial outing could never dream of. He'd be a perfect and very intimidating final opponent for whenever they decide to kill off the Legendary franchise.
5 Rodan A classic, instantly recognizable. Would make for a great secondary opponent, in a way that Titanosaurus was used in GvsMG. Teaming Rodan up with Varan would make for very dynamic battle, and they could finally share their iconic Ifukube theme.
6 Biollante I know when making an environmentally conscientious film the immediate tendency is to go with Mothra, but I always thought Biollante was better suited for that message.
7 Battra If they do decide to go down the Mothra road, I really don't want them to skirt around the Shobijin. They are an essential component of the character. But that doesn't mean they can't make Mothra more menacing. I propose that they replace Mothra with Battra, or have Mothra evolve into Battra mid-film.
8 Megalon God of draperies! Go on! Rise up!
9 Monster Zero Not a fan of Ghidrah showing up from space and wrecking "OH GODZILLA! WHAT TERRIBLE LANGUAGE!" for no reason. Perhaps make him Planet X's version of Godzilla, a tragic result of experimental weapons testing. In a twist, actually have the X-seijin attempt to help Earth.
10 M11
