The undead rankings are diverse and reaching the next stage is a form of evolution for each undead.
Undead Ranks (Physical cultivation)
1.Zombie
2.High rank zombie
3.Mutant zombie
4.???
5.???
6.???
7.???
8.???
Undead rankings (Spiritual Cultivation)
1.Wisp
2.Shade
3.Spectre
4.???
5.???
6.???
7.???
8.???
System Cultivation power rankings
1.Mortal Coil {Level 1- 5}
2.Transcendent {Level 5-15}
3.????
4.????
5.????
6.????
7.????
8.????
9.????
{Further information will be provided as the novel progresses. I probably should have put this up sooner, but the story was still slow burning.}