Aerial Ace. I think it already used the move in a trailer AND it's based on a sword technique. I can see it getting Shadow Punch thanks to the hand shaped cloth, too and I hope it'll get the usual WoW for ghost types, as not only will that further improve the durabilityx it has by default courtesy to its typing, it will also be 100% accurate due to No Guard.
Also, it might get Metal Claw and the unlikely Guillotine.
It should learn a new move called pierce that is steel type and either destroys any team defense(reflect, light screen), hits a pokemon using protect, and/or lowers defense. Maybe 60 BP. --- "Everyone step back. Me and this Jigglypuff are going to tangle and I don't want anyone getting hurt."