The manga has been running in the magazine since 2004, and Square Enix will publish the 19th and final compiled book volume on August 25. The story revolves around a game programmer named Keita who gets caught in a battle being fought by Kuro. Kuro is a Tera Guardian — a Mototsumitama or a guardian who maintains the Coexistence Equilibrium.
Kuro saves Keita's life during the battle and regenerates Keita's arm that Keita loses in the fight. This exchange creates a bond that unites the two in the battles ahead. Yen Press will publish the 17th volume of the manga in North America in October. source: ANN