(Mind having a bit of a plot recap, Sarrak? I remember there was some reason it was really bad to let essence die, but not all the details.)
(Once upon a time, there were ‘star gods’. Most nameless, but one had name and thus, grand ideas, creating the world we live in. Then, creatures came to be. My ideas on the purpose of creation range from selfish benevolence (by living and expressing themselves, creatures enriched both themselves and their creator) to eldritch farming practices (creatures having fulfilling lives is a byproduct of Essence enrichment process).
It went for a long time, while other ‘star gods’ were going mad with hunger they did not fully realize at first. Then, Catastrophe occurred. Basically, an attack from others/foreign entity, where our creator used its Essence to retaliate. Sacrificing its creation/farm, but not fully - and possibly infecting other ‘star gods’ with itself, for they have used its Essence to actualize themselves and got Names.
Essence is the Blood of Creator. And possibly traces of its very soul - which allows it to support our own souls, making progress possible (most probably, Essence has greatly intelligence development in creatures, otherwise there would not be so many races).
Full disappearance of Essence equals death of the world itself, which is partly/fully our creator - and full access to what remains for other ‘star gods’, who are even now trying to mess with inhabitants to gain trickles of Essence.)
TLDR: World is using Essence as a crutch for sloppy/intentional world-building by its ‘star god’ creator and it is absolutely indispensable for its functioning as of now. World without Essence might be possible, but this one can’t be it. Essence is its soul, immune system and replication cycle.