This article, Mercer Hallow, is property of Alvedrez.

Mercer Hallow''' (マーサーハロー ''Māsāharō''), or '''Gren''' (グレン ''Guren'') to some, is an S-class Dark Mage and one of the members of the Knights of Tartaros. He's an adept user of Take Over magic and employs a very special form of it called Grendel Spirit. He is most likely the weakest member of the knights but is useful for the HR department due to his temperament.


Mercer is usually seen wearing casual clothes, usually a white shirt, black coat, jeans, and black work boots. He has two hoop-like piercings in his left ear and a pinkish-red scar running across the bridge of his nose and onto his right cheek. His black is usually slicked back and trimmed very short, he also has a small chin trip right below his lip. Mercer's right eye is now a milky-white color due to an old injury he sustained during a tough fight with a troublesome priest that used Light Magic.


Mercer is a tired, annoyed, and nihilistic person that doesn't really take in much joy in life. He's described as the most stable of all the knights and doesn't seem to get worked up very easy. In fact, the only reason he is one of the knights is that his Take Over soul is ferocious and it supplies him with work. And while he takes no pleasure in the act of killing, torturing, or causing destruction he doesn't really care about the other people of Fiore. He can usually be found drinking in his room or the cafeteria in his free time. Mercer's not very sociable and doesn't really speak to the other knights.


Like the other knights not much is known about Mercer other than he was originally a foreigner from a poor family. Once he learned his special form of magic he killed his family, adopted a new name, and left home without ever looking back. He doesn't regret killing his parents, in fact, he believed that in a way he was saving them from the hardships of life.

Sometime a few years back he was recruited by Barbatos and Naberius when they tried to kill him and he ended up putting up more of a fight than they thought. He joined immediately, after they asked and never looked back. Although no one likes to admit it, Gren is most likely counted among the weakest members of the knights and has been kept around for the sole reason of his personality. He acts as an in-between for potential clients as his personality does not scare them off, but his magic supplies him with enough raw power so that he can fight back if need be.

Magic and Abilities

Take Over ( 接収 Teiku Ōbā): Mercer learned a distinct form of Take-Over magic from a rare S-class monster that had taken up residence in a nearby cave, it had been feeding on the flesh of the unweary. He impressively dispatched it with nothing more than a sword and took its soul.

  • Beast Soul: Grendel Spirit: Mercer's distinct Beast Form is that of a 7 foot tall white beast. It has arms that reach to the floor and a pair of small, muscular legs that can cave a man's chest with a single kick. The form has a set of jagged, shark-like teeth that hang slightly over the mouth, couple this with monstrous strength and poison spit and this form is something to be reckoned with.

Superhuman Endurance: Not only is Mercer able to take an enormous amount of punishment in his Take Over form, but in his regular, human form. Over the years, Mercer has learned to grow extremely tolerant to pain and now only the strongest of blows seem to have an effect on him.

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