*God Realm - The Kings Room*
The death of a Seraph wasn't something that was kept under wraps.
Seraphs were second only to Gods and were treated as such. The bright individuals that were capable enough to attend the academy but couldn't reach God level requirements, were often used to fill open Seraph positions. So for someone so gifted to perish would not go unnoticed.
Every being connected to the One Core could feel such a powerful connection vanish. Every God and every Devil, felt the impact of when Fydos was slain.
The slayers didn't quite realize it yet, but Fydos's death sent a ripple through the Heaven's that could no longer be undone.