On the rare occasions when they couldn’t regenerate anymore, so grievously wounded in battle that their immortal bodies could no longer heal, the Undying could move themselves into their necrothralls instead. It was why the Resistance had called them liches. It was an imperfect solution; even when maintained, the bodies rotted slowly around them and lacked the regenerative qualities of the near-impervious originals. Helena suspected this was why Morrough was so interested in transference—the method had the potential to allow the Undying to move into living bodies instead.
