"It's a Deal!" Bill hold out his hand which is now on fire and before the deal can be sealed; a black flame like figure appear from Bill's body and place itself between Bill and 'Stanford'. "Hey! What do are you doing, get out of the way!" Bill narrow his eye at the figure.
"Wrong twin." The figure said in a soft feminine childlike voice.
Bill blink in surprise and use his power to lift 'Stanford' up and remove his gloves. "Well what do you know, you're right, Kid. Looks like I owe you one." With a snap of his fingers Stanford and Stanley switch clothes.
"If you listen to me more often you would have been out of here by now." She sigh softly as she let her power form a cage around the younger Pines twin to prevent them from running. "I'll get what you need out of them but I'll need all four of them and a room."
"Have fun, Kid!" Bill blink them into dungeon before leaving to find the rest of his friends.
"Now then...lets begin." The Pines can't see it but the dark figure is now grinning, she might not like hurting children but she has a job to do and who is she to say no to a little stress relief?
Small back hands not unlike Bill's appear from black flame like cloak around the figure and hold the Pines in place and wrap themselves around their mouths to keep them from making any noise. "Eenie...meenie...miney...you." The black hands slam Dipper against the wall to knock him out before dragging him to the torture table and tie him down.
"He doesn't want to be awake for this." She explains to the struggling Pines as the black hands remove Dipper's shirt. She hold up her hand to show that it is also covered in black flames with claws at the tip. "Twinkle, twinkle, Dipper Pines. How I wonder what you are~" She giggled as she use her claw to carve Bill's circle on his back, enjoying the muffled screams of his family.
...She might have spent a little too much time with Bill...oh well. Nothing she can change about that. She continues carving Bill's circle into his back before carving a Pine tree at the base of his neck. "Next Pines." She said once she done, letting the black hands drag the unconscious bleeding boy into a cell and close the door behind them.
Mabel is crying for her brother as Stanley and Stanford are struggling to free themselves while glaring at her. "No need to cry, Child. You can go next." The small black hands lift Mabel up, ready to knock her out when a loud muffled 'WAIT' was heard.
The black hands stopped as the figure turn to look at Stanford. "Yes?" She asked as the black hands around Stanford's mouth remove themselves.
"I'll tell you, just please don't hurt my family anymore." He begged as Mabel shake her head furiously.
"...Very well." She said as the hands drag Stanley and Mabel into different cells and slam the doors close behind them. "And you better not lie to me or the rest of your family will get more than a nice looking scar."
Bill smile happily as he watch the chaos that is now spreading to the rest of the world. "Isn't this beautiful, Kid?" He asked the dark figure.
"Stop calling me kid." She growled. "And you said you'll give me this world to play with so you better fix everything before you leave."
"Jeez someone got out the wrong side of me today." He laughed. "And I'll fix everything before we leave, they'll think they managed to trick me into being destroyed and they won't even remember you."
She nods. "Good. I want to see how this world will play out."
"It reminds you of your world doesn't it? Just without the light and dark magic." He glance to look at the figure.
The dark figure smiled sadly as she watch the world burn. "It's almost like it, yes." She said softly as she let light bleed into her flame like cloak and pull down her hood to reveal a young female that looks human.
She is naturally born with two tone hair colours, the top is bright sunshine yellow while the bottom is dark black, she keeps her hair short but messy. Her sleepy looking dark eyes hides her sharp mind and her innocent face hide her dark sadistic desires.
She is bonded to Bill till the end of his time as of their deal. Her loyalty and friendship for his loyalty and friendship, it is a good deal for her; seeing as she was denied that in her world because of her magic.
In a world were the light and dark are at war with each other, to be born from dark and light parents did not give her a good life. Even if her Father is royalty and her Mother is a noble. Her mother's noble blood and powerful light magic kept her alive. Alive but living a lonely and hated life.
Bill gave her everything she craved her whole life and she would not allow anyone to take that away from her. Even if he ignores her voice of reason during his fit of madness; she has shown she will not hold it against him. She will protect and defend his one and only friend.
From now and till the end of their lives.