A towering alien with a brutish cross of porcine and bull-doggish appearance, Kilowog is renowned throughout the Green Lantern Corps as the primary trainer of the Corps' newest recruits. The Guardians of the Universe recruited Kilowog, a gifted genetic scientist, from the planet Bolovax Vik, located in Space Sector 674. Kilowog was trained by Lantern Ermey (reference to Gunnery Sergeant R. Lee Ermey), who would often use the word "poozer", which means "useless rookie" (a word Kilowog would later adopt, albeit in a friendlier way). In the middle of a particularly arduous training session, Ermey had Kilowog and his fellow rookies help stop an attack on a group of Lanterns, one of whom was the future renegade Sinestro. Ermey, fatally wounded in battle, commended Kilowog on his abilities, telling him that he had the makings of a great leader. In addition to serving with distinction as the Green Lantern of that sector, Kilowog also began to spend extensive periods of time on the Green Lantern Corps' home planet of Oa instructing new recruits on how to handle and best utilize their power rings. In this capacity, Kilowog acted as the first trainer to a young Hal Jordan, the ring-recruited successor to the slain Abin Sur of Ungara, the Green Lantern of Space Sector 2814. Kilowog and his new recruit helped the Guardians confront Abin Sur's murderer, the hive mind interstellar malefactor known as Legion.