(black)Wargreymon was my favorite digimon, but he is a mountain buster at best(as I know) with a decent speed, but not a speedster. The lantern can defend against his attacks. Though I didn't see an attack from GL that would one shot him.
... I fail to understand how literally EVERY other media and fan with a decent artistic streak can create a better looking and more realistic interpretation of the traditional Green Lantern costume than the actual Green Lantern movie had.