There are many causes of bloodline mutations.
Take Cang Xu as an example, his body was soaked in the Nether River and then the corpse-splitting healer took away his body to use as an alchemy material. Various factors prompted his bloodline mutation. This process is completely irreproducible.
"To already maintain nearly the original aptitude is quite good," he said.
"My life's opportunity has now appeared, right within the squad leader's grasp!"
"What I truly need is a Spell to detect undead aptitude that can identify my undead bloodline. Unfortunately, such a Spell is only possessed by those with a middle-level Soul Vein inheritance and is clutched in the hands of the ship ghost."
As an Undead Mage, Cang Xu couldn't, like other survivors, use a Magic Potion test to find out his bloodline.
Because this wasn't within Zi Di's realm of knowledge.
