The people involved in the Cadens' perish were core members of the Great Four, and ordinary family members had no access to such secrets.
After the Cadens were destroyed, the Great Four never mentioned the incident.
However, some rumors spread.
Some people claimed that Nicholas took his life out of guilt. He ignited the fire in the Cadens’ villa and attempted to repent for the sins that he had committed with the flames.
Some people also said that the Cadens had offended someone of authority