I can't believe we got an enemy with a fancy looking clothes.
> Shiage piloting a mecha
Old characters don't suddenly become relevant in this series. You're introduced, briefly important, then either forgotten or relegated to brief comedic relief from then on. There will surely be a new girl introduced to help Touma out when that happens.
apparently that is saint germain whom may or may not be multiple people. also niang niang i believe is just out of shot because the guy who took the picture did that.