Aerith herself?
The Heliotrope bounty-Refers to Ilfalna(Aerith's mom).
Following tragedy most final-Ilfalna dies.
Descent gains potency-Using MrSchpagge's idea, Aerith is stronger than her mother.
Ascend on with the great chronicle-Great chronicle might refer to holy/the lifestream, where Aerith combines with(ascends on) it.
