The next day some of Lilith's brothers went to college while her younger ones went to school. She would have gone to school too but managed to fake a cold to not go. Conveniently, her 16 years old brother Brian did the same strategy too, leaving them as the only ones in the house as their parents were working, Lilith giggled taking advantage of this opportunity to use her new power.
She went to Brian's room, realising he was taking a shower, she took all of her clothes without shame and sneaked her way into his bathroom, Brian not knowing he wasn't the only person in the house.
Lilith quietly opened the door and the sounds of the water drops helped her to disguise her attack. Then she quickly wrapped her arms around his belly.
"Wha-what the hell!! Lilith!?" Brian just turned off the shower and tried to struggle but somehow his sister's strength was bigger.
"Don't worry, I have bigger plans for you little bro, for us!" Lilith said while Brian felt his body different trying to move, like his butt was stuck at Lilith's crotch!
"What the fu-!? Mmmph!" His mouth was covered by one of her hands, the process was quick as his legs and feet merged with hers, being a torso growing in her crotch at the moment.
"I know you were some of the ones that spread the 'Lilith is another brother' joke, so why not making it real? Heehee" she whispered to her younger brother's ear, looking down at his constantly shrinking penis until there was just a smooth surface of skin below Brian's belly.
Brian tried to use his arms but not enough with his punishment he realised his arms were also shrinking, sucked by his own torso, with his whole body shrinking together and reduced to start to take the form of a tubular pilar of meat with veins. "Mmmph... MMMPH!" Saliva no longer came from his mouth, a stickier and white fluid appeared instead.
"Looks like you're getting exciting. I can't deny it, having a male part is feeling amazing!" Lilith said removing her hand from her brother's mouth, smiling at it covered by semen.
"Lilith!" Brian kept shrinking, he no longer had arms but a mere torso with a head that began to get a pinkish color, while two sacks of meat formed below him, as tennis ball sized testicles. "Li... Lith..." Were his last words before his head acquired a phalic shape, eyes and nose shutting by being covered in skin, and his mouth turning into a small hole that shot the rest of his sister's male juices.
"Aw yes!!" Lilith screamed holding her "brother" with her whole hand, still vomiting her cum until the last drop. "Ah~ so the amulet wasn't a scam after all" she said looking at her 8 inches long and thick cock that was now part of her. She lifted her testicles in front of a mirror and realised that her vagina was still there, hidden by her balls. If you saw her naked she could easily pass as a man with her flat chest if you didn't look much at her face, but then she turned around and gasped looking at her pumped improved ass, it wasn't the biggest but definitely better than her previous one, maybe unconsciously she transferred the rest of the mass of Brian to her rear.
"Oh my~ thank you so much little bro, I forgive you for your mean words after this~" she slapped her ass. "But how am I going to hide this thing?" Then she remembered about turning herself back, which did immediately. The penis shrunk and her butt deflated until she looked like her original self, while Brian's mind and soul was moved to the amulet, unable to do nothing but see through the hanging accessory of his evil sister.
Lilith tapped the amulet with one nail. "Are you comfy there Brian? I hope so, not that it matters, you're just the fuel of my ascension and there's not going back! You'll be there to help me with a couple of things more~" she giggled stealing Brian's clothes that perfectly fit her, thinking what more mischief could she cause.