It's more than possible for the PC to die in a non-literal sense. Just look at the Major Arcana of the Tarot. "Death" may be the final boss of Persona 3, but in the Fool's Journey, which is to say: the story told by the numeric progression of the Major Arcana, Death is in the middle, representing a turning point, or the end of one thing as it leads to another. (As an aside, the actual "worst" of the Major Arcana is probably The Tower, which represents catastrophic failure.)

Granted, this may be impossible simply from an implementation perspective if there are more Warrior of Light title drops outside of the MSQ than I think there are. (CT and Coil come to mind, both of which are now MSQ continuity-broken, but I think the rest are WoL free.)