User blog comment:B214/Question and Answers 3/@comment-75.93.25.66-20140626234344/@comment-1359322-20140627004601

Based on these statement in Volume 12,

"It’s Bikou who is spinning around his nyoui-bou(Ruyi Bang). Next to him a gigantic golem, Gogmagog, is blowing away an army of Grim Reaper with it’s gigantic arms. Then one of its arm turns into a machine gun. I also saw Kuroka's and Le Fay's magic attacks. Arthur is wielding his Holy-King sword and he eliminates hundreds of Grim Reapers. The one who is moving in god-speed and tearing the Grim Reapers is Fenrir. –It’s the Vali team."

And also the fact that Arthur is on par with Siegfried as a swordsman, i would say he's pretty much powerful enough. Of course, it'll be preferable if he becomes stronger.

I believe i was one of those that commented that Arthur should receive an Artificial Sacred Gear from Azazel.