Greed Dike is an Empire led by a tyrant known as Orion, set on conquering the rest of Babel for the sake of power and control. It's current territory can be found on the East side of Babel and to the East of Northern Pride, and the closest mainland point of Babel to the West of Wadatsumi.
See its exact location below:
Although no chapter has currently been released that features Greed Dike in particular, it still plays a vital role in the Events of the Sacred Stone Memories.
For a complete list of Units from Greed Dike, see here