The Kusakabe Clan is a Onmyouji clan that follows Buddhism teachings and has a long-lasting history of demon exorcising. Having demonic genes in their blood and higher magic aptitude compared to normal humans, they developed their own style of swordsmanship and magic, resulting in the creation of Onmyoudou. They were rivaled by the Azo Clan. The era in which their made the most progress was around the time of World War II. By that time, Ryouichi Kusakabe, the son of the Kusakabe leader and also a genius in magic, developed a great deal of new techniques, pushing what an Onmyouji could to to the utmost limit. However, as his hunger for knowledge was too great, he pushed his researches too far and indulged himself in Western magic, which was considered unorthodoxy to the Kusakabe teachings, resulting in his exile.
Another aspect of the Kusakabe is the practice of forging demonic swords, which absorb powers of the demons they have slain. Their efforts produced the legendary Kusakabe Seven Swords, a set of seven katana with fearsome power. Ever since the seven katana came into being, there had been a tradition of appointing each the katana to each Kusakabe house for keepsake and for the power balance between factions. However, in the 30s of the 20th century, Misao Kusakabe, an exceptionally powerful female Onmyouji of the Kusakabe, had won the right for two katana. Her victory led to many criticisms, as having a female leader was unheard of. For this reason, Misao left the village out of disgust, bringing two of the seven katana with her. The Kusakabe swords were then renamed as the Kusakabe Five Treasures.
In 2002, yet another scandalous events happened to the Kusakabe. Misuzu Kusakabe, daughter of the Kusakabe leader of the time, achieved an impossible feat: seizing all five katana of the Kusakabe Five Treasures. This event was considered even more outrageous than Misao and Ryouichi's cases. Her position as a woman was already disadvantageous for gaining support, but as she even monopolized all of the katana and crippled her own father in the battle for Doujigiri, the final and also the strongest of the five treasures, her reputation came down for the worse. Consequently, Misuzu left the village with her mother, bringing the five katana with her. This enraged other villagers, prompting them to send assassins after Misuzu, although they never once succeeded.
By the end of 2009, Misuzu returned to the Kusakabe village, bringing back the complete set of the Kusakabe Seven Swords with her as a proof of her victory over Misao. This shocked other villagers, allowing Misuzu to gain the upper hand in convincing them to stop being too rigid with rules and traditions. In the end, the Kusakabe Clan accepted Misao and Ryouichi's researches to expand Onmyoudou further for next generations to come.
In the anime, the Clan was only mentioned in reference to Misuzu and Misao's history as exiles. The Clan had a rule of giving the swords to those who earned them in single combat and an unspoken rule of one per person. Misuzu had gone against the norm to attain all of them but had done so legitimately. Acquiring Doujigiri had involved her killing her father in combat which resulted in her exile from the Clan as they couldn't accept her as the head of house afterwards. Likewise, the Clan frowned uponixing of Western magic with their traditional Buddhist arts.
The basic self-defense technique of the Kusakabe Clan is kendo. Their style seems to vary differently, applying not only to to single sword, but also dual sword.
Since the creation of the Kusakabe Seven Treasures, the Kusakabe also developed additional styles that could maximize the effect of the swords.
- Main article: Shikigami
Onmyouji of the Kusakabe Clan reinforce what kendo does not have by applying Japanese Eastern magic to their style, known as the art of controlling shikigami, spirits in the environment. In old times, summoning a shikigami required a full ritual, but it seems the Kusakabe developped special talismans which could skip the whole process; reciting the incantation for each spell is a must, however.