Sky armor for other characters?

[BumboBoy]

Do only 4 characters get sky armor? I’d really like to choose who is in my party for sky armor battles :/ I can’t figure out how to change who is in them if you can.

[Dr. Rudolf von Richten]

Only the four characters who initially get them (Glenn, Victor, Ba'thraz and Sienna) can use Sky Armors, probably because it makes the most sense for them story-wise.

Note that there are no differences between the characters in terms of stats or powers or anything else when they're in Sky Armors. The only things that matter are the armor and weapons used and the extent to which the characters' skills with all weapon types (used and unused) have been leveled up.