>>53330607It's the japanese name. Dynamax is called Daimax in japanese, from 大 dai (giant), so Eternatus is called Mugendaina.
Same for the upgraded versions of the gimmick, they use 巨大 kyodai (massive) and 無限大 mugendai (infinite) plus max, so Dynamax, Gigantamax and Eternamax are actually called Grandmax, Giantmax and Infinitymax