Having read numerous materials, Vaan wasn't unfamiliar with the different concepts of death in Chaos.
For example, the most common death was the death of the physical vessel. In this case, the soul would enter the cycle of reincarnation, reborn anew.
Of course, if the soul was particularly strong, having reached the divine rank, it could resist the call to enter the cycle of reincarnation, continuing to exist without a physical vessel instead, awaiting the time to reconstruct a new one or to possess another.
However, this wasn't considered death, but merely the destruction of the physical vessel.
Only souls that have entered the cycle of reincarnation were considered to have died from the destruction of the physical vessel.
