Description of few necessary facts about Horrid System: White Reaper.
1. Horrids: Horrifying creatures from another world or dimension. Every horrids have four common abilities such as regeneration, blood manipulation, changing the size of their nails, super speed. Aside from those abilities they each have their own unique ability.
Only thing they eat is human's heart. It's their staple food. They usually prefers heart of children, teenage boys and girls and any human who is under 40 years old.
2. Spiral of Death: The portal through which Horrids travel to human world( Mage's world). When horrids come, a whirling black portal opens in the sky. Generally, one horrid come through one portal or Spiral of Death.
3. Horrid system: A group of mages from the magical world abducts humans from non-magical world and turns them into human-horrid hydrid. Once those human from non-magical world gains this power they are also cursed with a system called 'Horrid System'. After being infected with the blood of a horrid a human can transform into them and gain their abilites. But their power comes with a heavy price.
And now, the reason why the mages abduct human from non- magical world is-
Pure Magic isn't very effective against horrids of highest hierarchy. Using pure magic only horrids of Lower rank or middle rank can be killed. But using it to kill horrids of upper rank is next to impossible. The casualties are immeasurable when a horrid of upper rank arrive in the human world. Most of all mages dies trying to kill the upper ranks.
That's why they came up with a way to fight Upper ranking Horrids with Horrids. But, after much expirement, they couldn't use their power. Because, people from that world all have pure mana. And, pure mana rejects those unholy magic power.
So, A particular group of mages, after many years of trial and errors, found a world other than their's. Moreover, Human of that world does not have mana. So, it was finally possible for them to use Horrid's power by implementing some sort of drug in those non-magic users. Thus the result was immense. Those Human-horrid hydrids could hold their own against horrids of Upper rank more than a normal mage could.