Time passed in a blink of an eye, while Bai Lung managed to reach ninth level of Nihility realm... a realm where he had basically become nothing.
He have become one with nothing, which means his journey to immortality has just started once he hits ascension realm...
Bai Lung is currently at nihility realm so, his life force is infinite... He can live until the destruction of cosmos.
Aka,
He can only live for 1 Qi Universal flow.
[ 1 Qi Universal flow: time period for 1 universe to born, fully expand and destroy itself ]
Which means to live further, he needs to hit ascension realm.
Ascension realm on itself isn't a major realm, as it's more like a judgement.
Once you reach peak nihility realm... You will hit your ascension time, a time phase where you have to become something from your own or create your own origin.
Only then one can step into half-immortal realm.
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