It never actually says an exact amount but it does say it fits in a "large gourd" so it could be something like what Gaara from Naruto has but it could be larger or smaller. Considering that he could confidently pour out a third of it (and probably the whole thing considering that he had to be stoped) into a large tub (because he can choose the size ill asume that it'll just fit just one comfortably) that is already has at least half full I would say that Gaara's gourd or a bit smaller is about right . this is mostly speculation because its never given an actual value.

The challenge is the point it was said before that the stairway to heaven is his training ground and the harder the challenge better the training it is also why dispite owning it he cant just jump straight to the 9th heaven

it could be that those in the divine realm or above are considered immortal so its more like a title then a realm it could also just be the author hadn't fully fleshed out the realms and so in straightening them one got mixed inbetween to add space or somthing

Chapters 415 to 419 he was there for context read from 402 or when he gets out of the mystic realm long story short he got back from the mystic realm and went into the dragon fissure, did some trials, activated a formation. Then he headed out of the "city" to the great ones treasury. To get there he had to go through the shadow realm meeting 2 banished immortals.

Very good if it was updated. Honestly im just ding this for the exp. But its still a good read and I think if you go looking you can find more chapters fir free elsewhere.

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