User blog comment:Serana Dawnsinger/Can undeath be cured?/@comment-32695213-20200204110633

Well since Naaru are beings of pure light and M'uru went full-void entity, Velen saved his "Spark" and managed to use his heart to make the holy Sunwell so I think it is very much possible, just also rare as long as there is some small bit of light in there?