What is "earthwar"

"Earthwar" is a story arc that was published by DC Comics, and presented in Superboy and the Legion of Super-Heroes #241-245 (July–November 1978). It was written by Paul Levitz, pencilled by James Sherman and Joe Staton and inked by Bob McLeod. The story arc features the efforts of the Legion of Super-Heroes to halt a massive intergalactic war involving the United Planets, the Khunds, the Dominators, the Dark Circle and the sorcerer Mordru.