Shoujo Grand Summoning - Chapter 61: the item to bring down railgun!

On an ordinary day, Lucius stumbled upon a strange, run-down shop. At first, he assumed it was abandoned—until he stepped inside.[You have entered the Universal Alchemy Store.][Congratulations! You are now the store’s owner.][Please craft your first potion.]Lucius blinked. 'What kind of joke is this?' But as if guided by an unseen force, he followed the instructions. Minutes later, his first creation was complete.[Love Potion: The drinker will fall in love with the first person they lay eyes on.]Lucius swallowed hard. 'Wait… does this actually work?'Before he could process it, the shop’s door swung open.Standing in the entrance was no ordinary customer—she was an elf. Long, pointed ears, mesmerizing green eyes, and a body sculpted by the gods. A visitor from another world.A dangerous thought crept into his mind.'Should I test it on her?'

After 20 years of dedicating his life to opera ever since he had quit the performing arts high school, he had failed at an interview. Losing his motivations, Jo Yunjae depended on alcohol to live out his days until one day, he had been sent back 20 years in time, to the day before his high school admission.

Right after getting the first-class chef’s certificate and before that certificate had been in her hands long enough to warm up, she woke up. Not only did she age ten years, she also gained two children…

—

At this time, her new daughter, who had lost two of her front baby teeth and spoke with a lisp, pointed at the TV screen and called out, “Dad!”

On the screen, the Film Emperor Meng Yan was extremely handsome and charming. Towards the camera, his gaze was overflowing with gentle and tender feelings. He raised up the hand that was holding hands with captivatingly beautiful bride. She was wearing a diamond-beaded wedding dress. At the bottom of the TV screen, the headline news was displayed in large font – Meng Yan and the rising starlet’s wedding of the century.

T/N: The second part of the summary is misleading. This isn’t a novel where the transmigrated main character clings onto the film emperor’s thigh.

- Description from Novelupdates

After dying in an oddly anticlimactic vending machine accident, Kazuki Ren is reincarnated in the demon realm—not as a hero, not as a villain, but as the only human male student enrolled at the mysterious Academy of Ruin, a school where all the professors are demon lords and all the students are powerful, beautiful she-demons.Ren is told he has one task: survive.But there’s a catch. The Academy’s darkest secret is about to awaken, and Ren holds a hidden power that could either destroy the demon world... or rule it.Now surrounded by seductive demons with hidden motives, eldritch tomes, forbidden dungeons, and twisted exams, Ren must master his ability—or be consumed.Magic, mystery, danger, and temptation await in this dark academia harem fantasy.