User blog comment:B214/Volume 17 spoilers./@comment-117.217.186.212-20140224111716

Vali might have already unlocked Ddraigs original ability but doesn't know it... Considering both dragons to be polar opposite of each other- the ability to reflect could only be countered by the ability to absorb. Vali absorbs the opponents power and makes it his own once he comes into contact with them... Additional power is drained by the wings.