Little sister, Starfire

Blackfire didn't had to think to hard about it, she knew there was nobody from that team of goody-two-shoes loser than she wanted to mess with as much as her dumb and weak little sister, she moved to the dungeon section of her ship and entered the first jail room where she kept her weaker and less pretty sister, she was tied up with red rope that showed off her boobs and ass, and her mouth was gagged with a white cloth, the only thing she was wearing was a black thong that Blackfire put on her after taking her clothing away, she had already removed her powers so she had no way to break the ropes tying her up.

(reference: https://wimg.rule34.xxx//samples/7628/sample_0c822a4f51c0c98d2e5c0e13e486c46c.jpg?8703798 )

"Oh hey there little sis, I'm so happy to see you again, and in just a fitting attire" she said sarcastically and mockingly.

Starfire stare back at her angrily, she was used to her sister screwing her over but this was a new low even for her, she tried intensively to focus her emotions so she could blast her with her eyes, but it was useless, her powers had been totally removed and she had no idea of how to bring them back.

"Oh look at you, trying to be defiant, it's cute" Blackfire said as she condescendengly petted her head as if she was a little pet, which is how She tought of her sister now.

Starfire growled as she tried to pull her head away not wanting to be touched by her.

"Oh Starfire why are you so mean rejecting your big sister? and I thought you were supposed to be the nice one" she said giggling as she took her hand to her mouth in a noblewoman's laugh pose "You know you look cute with that muzzle but hearing you doing nothing but growling like a dog will get tiresome and boring soon" she said as she roughly removed the gag in a single pull causing Starfire to whine in pain.

"You won't get away with this sister, either me or my friends will escape and beat you yet" She said in defience, which caused Blackfire to pretend like she's yawning in boredom.

"Jeez do you always have to put on the self-rigthous show, you hero types are all so boring and predictable, why don't we skip the whole her and villian argument and just skip to the best part" Blackfire said, Starfire had no idea of what she meant by the ´best´ part, until she forced her mouth against hers in a tongue kissed longer than any she have had with Robin, her eyes shot open in surprise and disgust, both for how wrong this was to do with her sister but also for actually feeling like she was enjoying it, her nipples getting harder and her pussy beggining to twitch in excitement, her clitoris growing even more than her nipples, as Blackfire broke the kiss there was a string of saliva still connecting their mouths "What's wrong sis? no more heroic speeches? I knew you were a slut, just a single kiss and you're just putty on my hand for me to play with, I guess your supposed heroic spirit wasn't that big after all"

Starfire looked away as she blushed in embarrasment and shame, her silent was mostly because of the shock of what Blackfire just did but she was right that a part of her at least did enjoyed what she did to her so she feared that what she was saying about her was true.

"Alright now how should I play with you?" Blackfire start to consider how she shall proceed in not just molest her sister but also break her will into an obedient slave.