I like your version of death here. although, lore question.
further exposure with death (in the future), essence wise or soul wise, would that or shouldn't that strengthen the protagonist's connection to his soul on the "other" side? if that won't make him stronger than the average STRONG man wont he at least be incredibly "visible" to mages, making him an anomaly, making him a target sealing the mages' fate, you know, cuz death.
sorry been playing too much pillars of eternity. also, maybe (modulate or put echoes) in death's voice deeper? darker? thinner? cortana in the halo 3 e3 trailer style?
whoever's writing is really good.