[RWBladewing]

Originally Posted by Asamidori

Spoiler for Stuffs others came up with:

Raven's blastia runs on his life force instead of with a core. Since spirits come from the core, Raven's not affected by it.

Spoiler for ending:

Yeah I guess that makes sense. I thought I remembered a character expressing concern that his blastia would stop working and he confirmed that it might, maybe I just imagined that though. (Of course even if that did happen it doesn't necessarily guarantee he'd have known that for sure anyway so you are most likely right.)