I'm 90 years old and the system tells me it's time to create harem - Chapter 23: We’ll go to hell together!

A massive underground labyrinth awaits in an alternate world of swords and magic. With a game-like system much more familiar than spells and magic circles, Beatrice has managed her magic and risen to the position of “strongest”, but she still has her worries.

“Bghohhh!! Bshrrrr…mumble mumble…”

“B-Boo Boo! Stop! Stooooooop!! I’ll…I’ll be crushed!? I-is my, ah, love being tested!?”

Who is the legendary man named Boo Boo who, just by taking a nap, can overpower the Level Cap Holy Swordswoman? A thousand meter dragons and a proud elf girl will also show up, so what exactly is going to happen with these residents of another world!?

“Why is the thing you summon always so strange, can’t it be a little more normal?”

Lu Yu looked helplessly at the guy who was waving his tentacles in front of him.

“Who made me look up to see you every day…”

- Description from novelbuddy

Wu Lai was an ordinary high school student. One day he was struck by a flash of lightning from a different world, and suddenly entered a fantastic world full of magic and swords. Since then, he started a totally new life. In this supernatural world, he had his ups and downs, experienced numerous battles, subdued powerful evil beasts, and fell in love with a belle. His nickname “Demon King” was remembered throughout the ages there.

Stay or return was a question. In the face of this choice, Wu Lai, with the nostalgia and gratefulness for the original world, finally chose to stay…

Here was the legend of “Demon King”…

- Description from Novelupdates

After waking up in the body of the Young Master of the Luo family, he finds he has the knowledge of hundreds of games and Light Novels. However, he finds his Dantian is crippled, so he can’t practice cultivation! Luckily, he has the Upgrade system.