User blog comment:Ixarising/High School DxD Dream Battle/@comment-24421137-20140128015808/@comment-1359322-20140128020500

Azazel, just like Cao Cao said, Azazel is a scientist-type warriors that researches on their opponent until their battle strategy is flawless for the next time they fight them. Azazel probably knows all of Vali's weakness.