Zanagamaru (or Ketsunaga) is an agency in the realm of Zanaga. Its main aim is to protect the realm and preserve peace and justice. The Zanagamaru agency has a number of powerful members who are loyal to its cause. Some of these members are Nata Alfred and Hanashi Kitsuchi .

Zanagamaru has a wide number of bases, and protects even in other realms such as the Tyrin realm. Ketsunaga also recruits young new members and trains them to become strong slayers. They usually recruit members that seem to have great potential.

The Zanagamaru is divided into squads which are ranked according to their power levels. The three types of squads are High-ranked squads, mid-ranked squads and low-ranked squads. The Necro squad is known to be the most powerful of all the teams in the agency and takes on death rank missions. It is also known as the Zanagamaru Assassins and is led by Nata Alfred.