Black Doom was one of the fiercest Sonic villains who ever appeared, but that could have been due to the fact that he was really a Shadow villain. His darkness abilities were certainly impressive, but what hurts him is his lack of speed. GL is likely faster and his constructs would quickly weak Black Doom. Stewart wins in a battle of endurance and his Willpower shall not falter. After all, he does have his military experience to fall back on! Green Lantern (Stewart) wins.