Tasker

In the anime, Tasker is the result of the 6 Key Spirits brought together. Tasker is said to be the power that created and can destroy the world. It has the ability to control all Spirits (Ex-Machina was the only Spirit that couldn't be controlled by Tasker). Tasker needs to merge with the true savior, who appeared to be Zed (Zed, Mirred, Noa, and Sagiri are considered saviors because they were chosen by key Spirits), and its goal turned out to be the creation of a world that only included Spirits. Zed was able to stop Tusker by - due to the influence of Zico, who appeared in his conscience - separating himself and Amil Gaoul from Tasker. Once Zed separated Amil Gaoul, Tusker was thrown off balance and defeated.

Tasker's abilities consist of close combat fighting, the manipulation of other Spirits, the original 6 key Spirit's abilities, and the unleashing of meteor showers that destroy the land. (Source: Wikipedia)