What happened to Elysia in Honkai?

Excuse me, could you elaborate on the events surrounding Elysia's story in Honkai? I'm quite intrigued to know what exactly transpired that led to her current state or the significance she holds within the narrative. Was there a pivotal moment or a series of events that defined her character and role in the Honkai universe? I'm genuinely curious to understand the impact she's had on the storyline and how her journey has unfolded so far.