We're just one chapter away from completion now. The next chapter after this one is the final - but its nearly 200 pages in length (that's an entire volume for most series)! Therefore, Getter Robo G Chapter 5 will be released in two parts. Many thanks to OtherSideofSky for his translation.
Getter Robo G Chapter 4
In other news, expect a Mars and Dokuro no Yakata release tomorrow!