The mini-event is when she teaches you how to open the portals, right after izanami discovers the sword doesn't recognize her. There isn't no specific time. Are you sure you didn't do the event? You can't go to the festival without it.
No I did that..
So you ran every possible event. In case you should have the signals like this:
Even if you don't find "Not in the game yet." there's no other content for Asmedia.
Even if you don't find "Not in the game yet." there's no other content for Asmedia.