User blog comment:IamJakuhoRaikoben/Chapter 471: Until the Battle is Done, Review./@comment-25324252-20160201211858/@comment-7418318-20160202093613

Now it'd be interesting to know what kind of machine Wahl is. If he's purely mechanical, sand magic could work wonders in cloggin up his inner workings.

If he works electronically, Juvia's water could be devastating, since it could cause shortings (is that how it's called in English?) of his circuits.

Arc of Time could possibly also be a trump card, if Ultear ever returns.

And if everything else fails, Gajeel can eat him. ^^