User blog comment:Besteverunited/Do you think after the tartarus arc there will be a break in the anime or is the new manga arc designed for this reason?/@comment-7418318-20150227083944

Seeing as how they animate the 2nd light novel, maybe they'll do the same with the first one too. Though with it having Aquarius in it, it'd either have to be a falshback or happen before you-know-when.