This world only has a few selection of Demon Creatures that have been brought into this world by The Demon Grandfather, Khalfvyskov. He has bought a total of 10 types of creatures into this world each with their own unique identifier. These demons were created to life in the year of 55 AD, and they age at the same rate, with their age measured in days. The Demon Race in this world isn’t really frowned upon. Other cultures view them with respectful autonomy because they’re not demonic. They’re beautiful creatures that have the ability to understand others even past those surface-level rumors and stereotypes.
Khnavkiers. A direct demon-descendant from Khalfvyskov himself. They look like a combination of minotaurs, onis, and chimeras.
Among the creatures, comes Lesser Witches. They all come in different appearances, but that's their main form. They can fully evolve into a demon witch through countless bloodshed.
(and many more)
Each Demon Creature in every different subrace will age slowly after 23 years. At the age of 23 is when demons get their abilities and powers after undergoing a process called Demonization. Demonization happens when every cell in a demon body becomes unstable due to the changing effects of black blood cells. The unstable cells turn into Demon Core Cells, which each develop their own unique abilities and powers. After this process is done, the aging factor is slowed down during that 23rd year. In a dormant section of a demon brain, those powers and abilities become a part of their survivability. They are powerful to their own accord. All Demons have two hearts.
It takes 975 years for a demon to reach 155 years old (biological age). The oldest age they can live up to is 9,000 years old. The ages of baby-23 needs to be dismissed, because those years are when they age much like how humans age.
975 - 23 = 952