I'm assuming it's some kind of religious ability due to the cross in the background. Perhaps she can sense people sins and punish them a bit like Ghost Rider.
Her "character archetype" generally is the straight-laced type that doesn't like these things.
Both she and Jenna are cute.
Hmmm... does her ability somehow deals with "analyzing the inner desire"? Because that is the only thing that comes to mind with her initiating the explanation like that, but she is totally Kyoka's fan.
I'm guessing her ability is something that either allows her to feel (or even absorb) another person's essence, which probably gives her a feeling that Yuuki is connected to a god as well as his sister; or her ability is something that directly opposes Yuuki's position as a slave. Beyond those, I can't imagine any other reason why she'd loathe him if it has something to do with her ability.
Thanks for the chapter! Whether regular Mato or this pocket Shangri-La, I really enjoy the "regular home and every day activities, but in a beautiful, otherworldly space" aesthetic.