Pure Bloods: A minority but powerful of them are in this level and do not have a single drop of human blood in them. They can change a human into a vampire and only a handful of them will do that. Examples from Vampire Knight: Kaname Kuran, Shizuka Hio.
Nobles/Rank B: Nobles are very protective of Pure Blood vampires. They are powerful and most of the Night Class students are in this level.They can control ice,fire...wind....etc...
Level D: Humans who are bitten by Pure Blood vampires will come to this level, and it’s the fate of all Level D vampires to fall to Level E. Only by drinking the blood of the Pure Blood who bit them could turn them into a true member of the night soceity, or vampires. They cannot take in blood tablets, which can be taken in by other vampires. Examples from Vampire Knight: Zero Kiryu
Level E: The inevitable fate of Level D vampires. Unless they drink the blood of the Pure Blood who bit them, they will lose their sanity as they could not completely accept their vampire instincts and this class is seperated from the other classes.