Killix_Kreed
I can understand how the protagonist's evolution works, he for being an S rank monster gains more status and abilities than low rank monsters making even he being low level doesn't change the fact that he is a scary S rank monster , this is because the system has given him the ability to improve his bloodline and increase his rank, which I assume is not possible for others and is only accessible to him
If you put species into categories being the lower rank and the higher rank the MC's species evolving to a [Zombie Lord] means he has become a higher life form or entity from a Zombie(Lowest-rank) -> Zombie Lord(Higher-rank). So to put a dragon is also on the Higher rank of the species, a dragon can topple down a country to most fantasy stories a zombie lord a higher life form is comparable to a dragon.