Westros' obsession with Lyra stemmed from the fact that she was a miracle of his own making.
Her human physiology exceed that of ordinary beings, and even Stellar Devourers rarely reached her level of capability.
Her unique superpower, Vitality Glow, granted her not only incredible healing abilities but also devastating offensive power.
Lyra's parents, wrapped up in the process of her creation, had no idea just how extraordinary she truly was.
It wasn't until Robin and Isadora were created that Benedict knew about the truth.
After Tyro and Seren's deaths, Benedict had been tasked with secretly protecting Lyra. This was why Ansel couldn't just kill her outright; he resorted to the underhanded tactic of using Soul Spikes, never imagining she would survive.