There were a lot of things Dalvin was expecting to hear from Gaia about their current situation, but definitely not this. Seeing his confusion, Gaia sighed and elaborated further.
"Every world has its lifespan. So does every star, every galaxy, and even every universe. Once that natural lifespan comes to an end, the entity in question is supposed to perish."
"However, much like cultivators who can extend their lives by ingesting energy, so too can worlds and other entities extend their lifespan beyond that of what was given. However, much as cultivators suffer under lightning and thunder tribulations due to the rules, entities also suffer if they extend their lives through something called the Apocalypse."