User blog comment:Miskos3/Fairy Tail Chapter 391: Gray vs. Silver, Review/@comment-7418318-20140704072547/@comment-7418318-20140704083614

There wouldn't even have been a reason to elaborate, a single sentence would have sufficed. Like "I had to search long and work hard to gain this power, but I did it for my revenge." for example. Easy to fit in without losing the focus on the battle.

And there won't be an "easy" solution like in the Zancrow fight. Gray already did something very similar to what Natsu did by using the power from Deliora's ice, but it didn't work.

The problem isn't that it makes no sense, but that it's so completely overused. Slayer magic of any kind is supposed to be "Lost Magic". And look how many Slayers are out there. 7 Dragon Slayers, 3 God Slayers and now the Devil/Demon Slayer. I don't remember any that has more users than this supposedly lost magic.