Correct me if I'm wrong, but while area specific cards can generally be found in GHQ, an exception to that rule would be Runa Kamiwano and Kaede Misu.
Personally, I missed Kaede since I don't think I ever even saw her because I seemed to have completed the stage before they updated the lists of cards for the area. I only occasionally see her pop up in event areas, and I probably won't get her anytime soon unless I spam reveals like crazy ;_;
Nutaku ID: 309624
I got Runa when she first came out, either from normal gacha or event stage, whereas Kaede is like some elusive rumor to me xD (IIRC she was / is in the event gacha).
According to the wiki here, Kaede can be found on the last part of stage 13, which was likely one of the blank slots I saw when I went through the stage a few months back.
Nutaku ID: 309624
all stage cards can be found in explore bonus stage