Webnovel ch 60 settings.
Here's ainz racials and it seems there's a separate classification for monsters, will it be used in the light novels? who knows
Ainz is a Skeleton Mage (Race) 15lv, Lich (Race) 10lv, Demilich (Race) 5lv, Overlord (Race) 10lv, True Necromancer (Class) 10lv, Chosen of Undead (Class) 10lv, etc.
Monsters are different.
Monster are not counted with Racial and Class levels, instead Monster Levels are used. This is added to Class Levels (If they have).
In the case of Brain Unglaus.
He was turned into a vampire by Shalltear. However would a Vampire’s levels (Same as Shalltear) be added to his warrior levels, no. He is a monster with Vampire (Monster ? Levels) added to his warrior ? levels.
This is what happened after Shalltear sucked his blood and turned into a monster.
And so there is a difference when a Dragon Lord reaches Hero class and a human reaches Hero class, the difference in monster level opens a gap between them. (Normal humans do not have a racial level, their first level is their class level.)
However for a Dragon to reach a Level 1 Warrior Class and a human reaching a Level 1 Warrior Class, in game terms, the experience needed is vastly different. I believe you can roughly understand.