Rather than eat the world for some lifespan and law fragments, he believes that it is a better idea to assimilate the world and use it to increase the size of his Cave Heaven. This is mainly because having more lifespan right now won't increase his power in any way, while a larger Cave Heaven would lead to an immediate increase.
Besides, he already has enough lifespan to fight with, and the problem of increasing the amount of lifespan he can get from the living creatures can be solved by increasing their population over time.
On the other hand, the problem of how to increase his strength is not something that can be easily solved over time. He needs to prioritize raising his strength at all costs before he can see a significant increase in his power.
This conclusion of his thoughts made him say to himself, 'Maybe if I need to spend my lifespan to comprehend the mastery of a pathway, I would prioritize gaining more lifespan.'
