Sadly, with the condition she was in, Mana was in no state to try and use any Charms to perceive the usage of Essence on Miki's part.  Not with having all of her Essence drained with this artifact.  She hadn't noticed the collar, not yet.  At first, she just wanted to thank Miki for her hospitality and just claim that she just needed to rest, realign her directions, and then could be on her way...but then she got that look.  She...she couldn't make her upset, she'd already done that with this whole mess.  "W-well, if you don't mind me staying here as your guest, then I suppose I'd be willing to accept..."  Good.  Miki had the girl on her chain.  She just needed to reel her in and she'd have the situation under control.