ok im at a loss here what the hell do i do with essence of growth i have like 10 of them but there's gotta be more than just sacrificing them at the anvil
You must go to the green NPC with the black plague mask (he is in his house next to the bar)
if you talk to him he will give you the option to ''transmute essences'' this will allow you to make empty essences become essences functional (it costs 200 to transmute each one), you can also make, for example, a muscle essence transform into one of size (this process will cost 30 to transmute each one)