Eila was a Wood Elf born and raised on the outskirts of Caial Brael on the Kojani Archipelago. During her youth, the terrible Oni spirits began to enter the Youngtree Forest near her home. The alchemists to whom Eila was born worked tirelessly to drive the Oni out, but to no avail. Slowly being worn out and driven mad by their quest, their credibility dwindled. Eventually, Eila's father claimed to have found the solution. With no one willing to aid him, he constructed this powerful weapon alone in his own home, accidentally triggering an explosion which killed dozens of wood elves including both of Eila's parents.
The angry Wood Elves banished Eila into the Youngtree Forest, where she survived for years despite the danger. She became a master alchemist and studied the Oni unceasingly, eventually reaching the same conclusion her father had. Then, she journeyed back to Caial Brael with the hope that she could convince the Wood Elves to construct the weapon, before the same fate that took her parents lives became her fate as well.