"Ōeyama Kaden" is a manga series that blends historical and supernatural elements, set in the Heian period of Japan. The narrative revolves around the legendary figure Minamoto no Yorimitsu, also known as Raikō, a renowned warrior and leader of the Four Heavenly Kings. The story begins with Yorimitsu being tasked by the imperial court to investigate and eliminate a series of disturbances caused by oni (demons) in the Ōeyama region. These disturbances are linked to the infamous demon Shuten-dōji, a powerful and malevolent figure who has been terrorizing the land.

Yorimitsu assembles a group of skilled warriors, including his loyal retainers Watanabe no Tsuna, Sakata no Kintoki, Urabe no Suetake, and Usui Sadamitsu, collectively known as the Four Heavenly Kings. Together, they embark on a perilous journey to Ōeyama, where they face numerous challenges and confrontations with various supernatural entities. The narrative delves into the complexities of their mission, highlighting the bravery, camaraderie, and strategic prowess of Yorimitsu and his companions.

As the group ventures deeper into Ōeyama, they uncover the dark history and motivations behind Shuten-dōji's actions. The story explores themes of loyalty, honor, and the clash between human and demonic forces. Yorimitsu's leadership and moral resolve are tested as he navigates the treacherous landscape and the moral ambiguities of their mission. The climax of the series features a dramatic and intense battle between Yorimitsu's forces and Shuten-dōji, culminating in a resolution that has lasting implications for both the human and demon realms.

The characters are richly developed, with Yorimitsu portrayed as a noble and determined leader, while his retainers each bring unique skills and personalities to the group. Shuten-dōji is depicted as a formidable and complex antagonist, with a backstory that adds depth to his character. The manga effectively balances action, historical context, and supernatural elements, creating a compelling and immersive narrative. The artwork complements the story, with detailed depictions of the Heian period's aesthetics and the eerie, otherworldly atmosphere of Ōeyama.