The secondary characters
Regarding the other secondary characters in the story, we haven't seen them for a while since the defeat, or even the last big fight between Rei, one of the Seiko sisters, and the other girl I'm showing you, against Uta.
We know we last saw them because they were training for upcoming events. Now look: we haven't seen Yuzuha, we haven't seen Sara, and we haven't seen other secondary characters either.
I think these are the friends who will have to grow stronger for the upcoming events, because we've seen it. They have a level they need to reach, and they haven't yet. So I suppose that's probably why. What do you think?
In any case, if we see them again, they'll surely come back stronger. The proof: look at Rei. We only saw her to finish the fight. You can see she's evolved.
Speaking of Rei, I'd like to see her fight more in hand-to-hand combat, using the martial arts and techniques she learned from God's army, and not just impulsively swinging her arms like whips.