[Pezz Talent]

Well technically OP is licensed, but so is Bleach, Naruto, Gakuen Alice, etc. But Viz Media doesn't go after scanlators for translating. And the reason why the anime doesn't follow the manga 100% is because the episodes usually go faster than the chapters, so they add fillers in between manga arcs so the manga has time to catch up and pass by it a little before they start the new arcs.