Earth King

Earth King is an unique kind of Zeppin in that unlike most zeppin it's not simply one but a set. it is the strongest zeppin in the entire kingdom of Grasse..

Overview
The Earth King is a set composed of a den den mushi and the entirety of the soil of the island of Grasse. This ground has been endowed with the loyalty, voice comprehension, telepathic link and ability to follow orders of a den den mushi(among other things) thus enabling the earth itself to move to the commands given to it by the Den Den Mushi it is linked to.

This effectively means that the Earth King is the super majority of the kingdom of Grasse and logically the zeppin is able to completely alter the landscape for truly massive feats of power.

The existence of this Zeppin is what keeps the world government at bay in trying to annex Grasse Kingdom as when fighting in their own turf Grasse is effectively invincible.