Board Thread:Wiki Discussions and Support/@comment-2140588-20150318152949/@comment-142748-20150404195649

Filler is never canon unless explicitly stated by a manga author, or the manga author having written it. Fillers often have out of character moments, inconsistent abilities and power levels, and often contradictory elements to the main plot otherwise. There are exceptions, but all of Naruto's filler arcs are non-canon.