Fantom had many things she enjoyed. Smiling. Kissing. Victory. Treasure. Napping. Kidnapping. Seeing others squirm. Squirming. The feeling of the sun on her face after a cloudy day. Gags. 

There was nothing quite like combining all of them at once. She returned from a little walk out of the ruins, walking back down until she saw her victim, her ‘friend,’ her foe - her recent plaything, Elissa the thief. 
“I’m back,” she said. “Miss me?” 

“I know… but I’m back now, sweetie. For a bit, at least.” 

Ancient ruins were great for storing things - like people, and treasure. Elissa was both. After a few hours of squirming, the poison had worn off and Fantom was able to escape - barely - from her bonds at the hands of Elissa. The pale-haired thief was a sweet thing; she could have done things far nastier to Fantom, but she’d showed restraint. And showed restraints, proving a certain mastery of snug bondage upo Fantom’s capture. As such, Fantom had decided to return the favor. 

Elissa was busy exploring the ruins for just long enough for Fantom to get free, using a sharp rope and a little ninja magic to escape, and then a quick spell to stun and put the thief to sleep long enough to explore the room and get her bearings. She spent a few moments exploring the area, checking for any traps. She wasn’t as savvy as Elissa the thief, but what she lacked in perception she made up in confidence. Confident that the coast was clear and that Elissa was stunned, she had gone for a quick stretch to feel the evening sun on her face. 
To her surprise, no time had passed at all. It was as if time was standing still inside the ruins. When she returned to the thief, she was just as she was when Fantom had left. 

This was exciting . That meant that these ruins were the perfect spot for a new hideout, a new lair, a new treasure chamber. Starting with the girl who’d come to kidnap her, the thief Elissa. 

Fantom snapped her fingers and summoned some rope, some tape, and her courage to welcome her new ‘friend’ to her storage space. 
First, she shared the same magical gag with Elissa, slipping it between her lips. Next, three very generous strips of tape over her mouth and lips  - sealed with a kiss. Fantom liked to think that she was nothing if not a good host! 
And then, since she already had the tape… quite a bit more. Another layer over her mouth, to the point that Elissa’s sweet, pretty lips were no longer visible. Then she used its magical adhesive properties to restrain her to the stone plinth where the two of them had been sitting earlier. Finally, she ordered the rope to wind itself around Elissa’s body, creating a magical seal that would alert Fantom if Elissa tried at all to escape.
By that time, Elissa was well awake. Fantom’s day was getting better and better, even if the tables had turned on the rogue.
“Mmmf.” 

“Yes, yes, I know, I know, you missed me. Or maybe not. I don’t know if you realize I was gone for quite a bit! Maybe that didn’t occur to you. I think I’ll have to keep you here by the way. I’m so sorry , dear, but a thief like you can really mess up your plans - even if you’re a nice one to have around and clearly talented.
My name is Fantom, and I’m a kunoichi - a magical ninja with training extraordinaire. And while you didn’t know what you were going to do to me, I know exactly what I’m going to do to you. You’re going to be my test subject for my new lair, and for all future spells. Don’t worry, I don’t have anything TOO cruel lined up for you… not yet, at least, not while I still have use of a squirming, moaning, angry thief. And as long as you know how to act the way I want, you’ll be a fantastic little ‘partner’. For example, I’ve got a lovely spell that will force you to do exactly as I say from sun-up to sun-down… and testing it on myself is just too hazardous.

Elissa’s eyes narrowed. Fantom knelt over her. 

“I’m sure you’ll be a good, squirmy captive for many years to come. Not that you’ll even realize just how much work you’re doing for me. 
“Mmmf?”

“Now now, don’t get too eager - I need some time to prepare new spells and potions.  If you’re too squirmy and too distracting, I’ll just have to find a nice cozy box or get a nice stone tomb for you to sit in until I decide to take you out, and that’s not as nice as being out like this, is it?”
“Mnnnfffff”! Elissa’s toes wiggled and she started to buck. Fantom leaned over her. She took Elissa’s chin in her hand, gently stroking down from her jaw before firmly, firmly grasping it in her hand.

 Elissa tried to look away, but Fantom turned her head back to face her captor. The ninja made eye contact with the thief, and she was grinning. She wondered if, beneath that heavy gag, Elissa was grinning as well.

“Hmm… you’re cute. I don’t know if you’d ever be a good business partner, but you’d have made a good rival. But I suppose that has to end before it even begins, no?”

Fantom didn’t even look at the magical chest that she’d touched earlier. She didn’t realize that Elissa had been trying to look at it, not avert her gaze from Fantom. She didn’t notice its purple glow until it opened.