Arkillo is the ruthless drill sergent for the Sinestro Corps. After sending out rings to recruit members, Arkillo would train the new recruits. If any recruits failed the tests, Arkillo would devour them whole.

After being forced by his Green Lantern counterpart, Kilowog, to retreat during the Battle of Mogo, Arkillo was bitter and enraged that his conflict with Kilowog was interrupted.

During the invasion of Earth, alongside the other Sinestro Corps members, Arkillo found his nemesis in San Diego, California. Arkillo did not hesitate to challenge Kilowog to a rematch and their fight to the death began. Kilowog was able to force Arkillo back and into a comic convention building. Arkillo lectured his rival, stating it was only fear that kept Kilowog from killing him. Arkillo became overconfident and was shocked when Kilowog threw an air craft carrier on top of him. Arkillo remained trapped under the debris as Kilowog removed his finger and took his ring away.