Though the two OFA members being mysterious shadows… what's the point in obscuring them so completely unless they're people we've already seen... or are going to meet at some point still alive?
Someone in 4chan said that maybe those two were corrupted OFA users, people that wielded the power for their own gain or maybe people like Stain that killed because of their creed. It may not be the case, but it would be interesting if not all the people that used OFA were good heroes and the first tried to ignore their existence.