User blog comment:B214/Volume 22 spoilers/@comment-9595671-20160825044804/@comment-9595671-20160825081024

And that could still work, maybe they could be minor antagonists. Malebranch is implied to become the villains of the arc but we don't know how they get unsealed.

Indra's war for example could be how it's members escape their seals, and Hades could be somethat responsible for their seal but does something or his prior actions add into them getting out.

So they could end up as catalysts that start the main problem in this arc. It might be a stretch, but we won't know until it happens... and that's why this arc is already starting to get exciting ^^