OK! After a break, I went for a redesign based on the feedback here and some ideas I had. I redesigned the Summoner, giving her clothing I liked better than my original concept, making her more dynamic, and adding a connection to the Archon. The "horns" around her head/face will be made of light and slightly transparent. This should indicate that she is somehow magically connected to the Archon she has summoned.
Here's the new Summoner sketch:
The Archon will be in a similar pose to the Summoner, showing that they are "connected". Instead of her floating, she will be on the ground with him looming large, almost enveloping the Summoner.