Las Noches is that sized based on one, possibly hyperbolic/exaggerated statement. I can prove, like I have countless times to you before, that Seireitei is large city sized, and no more.
Go to hell.
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"Why is everybody so ****ing stupid?"- Kim Jong Il, Team America.
Ulquiorra is country level because Las Noches is so large that it takes 3 days to walk across its side. And Gremmy's meteor is continent level as its half the size of Seireitei which is again country sized.
And Gremmy is the king of hax.
But he lost just because he was stupid and killed himself
Los Noches and the Soul Society are suppose to be about the same. Both LITERALLY house an equal number of souls to the real world. That is the premise of the whole series. When people die in the real world they re-spawn in Soul Society. If they are bad/evil they respawn in Los Noches. Super bad go to hell. When people die in Soul Society if they are good they respawn in real world and if bad in Los Noches. Sooooooo ya they are suppose to be huge....... Country size at least. Soul Society has 300+ districts each Japanese district in RL is literally a city size piece of land.
Gremmy can make anything with his imagination. Kaguya doesn't even engage Naruto through out most of the encounter in melee effectively at all. She herself is worried about using up her chakra over and over again so she must have some sort of limit. Gremmy could only not defeat Kenpachi because he didn't understand the range of his limit and made himself weak because he doubted himself for a second and made his own doubt reality.
Technically he does not, only limited by his imagination which is limited by his psyche. He could do anything. He literally encapsulated Kenpachi into the gravity of space. Kaguya can manipulate the environment but it seemed to be limited by her own greed of chakra which she seems to be limited by in her own statements. Are you trying to imply that there is no limit to Kaguya?