"K: The First" is a manga adaptation of the original anime series "K," created by GoRA and GoHands. The story is set in a world where seven powerful Kings, each representing a different color, wield extraordinary abilities granted by their respective clans. These Kings are bound by a system known as the Dresden Slates, which bestows supernatural powers upon them and their followers. The narrative primarily revolves around the conflict between two major factions: the Red Clan, led by the Red King Mikoto Suoh, and the Blue Clan, led by the Blue King Reisi Munakata.

The plot begins with the mysterious murder of a member of the Red Clan, known as the Homura. Yashiro Isana, a carefree high school student, is framed for the crime and becomes the target of both the Red Clan and the Scepter 4, the Blue Clan's law enforcement division. Yashiro, also known as Shiro, is aided by his loyal friend Kuroh Yatogami, a skilled swordsman and former disciple of the late Seventh King, Ichigen Miwa. Together, they seek to uncover the truth behind the murder and clear Shiro's name.

As the story progresses, it is revealed that Shiro is not an ordinary teenager but the Eighth King, the Colorless King, whose powers are unstable and dangerous. The Colorless King's abilities allow him to possess others, leading to further chaos and conflict. The narrative delves into the intricate relationships between the Kings and their clans, exploring themes of loyalty, power, and the consequences of wielding immense authority.

Key characters include Mikoto Suoh, the hot-headed and fiercely protective Red King, and Reisi Munakata, the disciplined and calculating Blue King. Their rivalry forms a central axis of the story, with their contrasting ideologies and methods driving much of the conflict. Other significant figures include Anna Kushina, a young girl with psychic abilities who becomes the new Red King after Mikoto's demise, and Neko, a mysterious girl with the power to manipulate reality, who allies herself with Shiro and Kuroh.

The manga adaptation closely follows the events of the anime, maintaining its focus on the high-stakes battles, political intrigue, and the personal struggles of its characters. The artwork captures the dynamic action sequences and the distinctive character designs, staying true to the visual style of the original series. "K: The First" serves as a comprehensive introduction to the "K" universe, providing a detailed exploration of its lore and setting the stage for subsequent installments in the franchise.