Green overseer

The green overseer is a rare variation of the overseers. It has a distinctive deep emerald green that cannot be mistaken with the common blue or yellow overseers. Because of its incredibly low spawn rate, most players will never encounter the green overseer if they don't look for it for many cycles. Bringing the green overseer's eye to moon heeds no special dialogue, since it is identical to yellow's and blue's eye. It has the same behaviour as the Blue Overseer.

Conditions of spawn
You have to play with Hunter, you can't be at the Wall. In Shoreline you have a 2% chance of encoutering one, elsewhere there is only 0.0125% spawn chance.

Trivia
It is never directly said to what iterator the green overseer belongs to, but it is implied to be No Significant Harrasment's, since your main mission with Hunter is to revive Moon, and in Shoreline is where you will most likely find it.