Board Thread:Wiki Discussions and Support/@comment-5407586-20141206094948/@comment-1207741-20141208064146

"Canon" is for in-universe information. Arcs are out-of-universe, and therefore aren't capable of being canon. There are grades officialdom to consider, but there's no question of "canon" on this issue.

(I point this out so nobody compromises their personal stances.)