Rikuo Nura, a part-youkai and part-human boy, grew up as the young master of the Nura Clan. Comprising youkai of all shapes and sizes, Rikuo treated the clan like family, however, he learned that he was the only one among his classmates who saw them in this light. To most, they were terrifying creatures of folklore who ate children and relished in bloodshed. Taking this to heart, he swore to live his life as a normal human. Normalcy, however, is hard to come by for young Rikuo. Complicating his goal are his youkai attendant, who under the name Tsurara Oikawa, goes to school alongside him; the young onmyouji Yura Keikain; and his close friend Kiyotsugu, who idolizes youkai and hopes to prove their existence. To make matters worse, rival youkai and other entities threaten to harm those Rikuo holds dear. If he wants to protect what's important to him, Rikuo must acknowledge his ancestry—that he is the grandson of the legendary Nurarihyon—and transform at night into a youkai, becoming worthy of being the next leader of the Nura Clan. [Written by MAL Rewrite]

In a world of constant war between humans and witches, there exist the "beastfallen"—cursed humans born with the appearance and strength of an animal. Their physical prowess and bestial nature cause them to be feared and shunned by both humans and witches. As a result, many beastfallen become sellswords, making their living through hunting witches. Despite the enmity between the races, a lighthearted witch named Zero enlists a beastfallen whom she refers to as "Mercenary" to act as her protector. He travels with Zero and Albus, a young magician, on their search for the Grimoire of Zero: a powerful spell book that could be extremely dangerous in the wrong hands. During their journey, his inner kindness is revealed as he starts to show compassion and sympathy towards humans and witches alike, and the unlikely companions grow together. [Written by MAL Rewrite]

Although everything the young duke touches perishes, his existence is far from lonely. His spirited siblings Viola and Walter, loyal butler Rob, and the eccentric witches Cuff and Zain are regularly livening up his secluded mansion. But it is the duke's flirty maid, Alice Lendrott, who fills him with the promise of a beautiful tomorrow and the determination to break this hellish spell cast upon him. The identity of the witch who cursed the duke has been uncovered thanks to Zain's unique magic and the help of Daleth, the leader of the underworld. However, the villain is a notoriously fearsome and powerful witch, who, enraged by the duke and his companions' trip back in time, torments them even from the afterlife. Moreover, an unexpected loved one reappears, strengthening the duke and Alice's hope to break the curse and finally close the distance between them.

An unaired episode of Shinmai Maou no Testament, bundled with the eighth light novel volume.