This Marriage Will Surely Succeed - Chapter 10

[Can the devil’s music bring happiness to the world?]From Jimmy Hendrix to Rachmaninoff, all the historical musicians who he meets in his dreams.The devil that presents itself as a little boy in love with singing.The devil’s blessing, given to such a tiny child.In the blessings of many devils,The boy’s song for the world begins.

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

One night she gets drunk and mistakes the most well-known Mafia boss for a Host* and intends to sleep with him.

“There are no heroes. In life, the monsters win.”

...

In 2106, [Mayhem Online], a fully immersive VRMMO game, was released. Soon, it dominated the world's economy when people could exchange the in-game currency with real-life currency and vice versa.

In the year 2107, Flynn Grey, a 22-year-old college dropout with an ambiguous history, joined in the fray of billions of people that had already started playing [Mayhem]. Hoping to uncover the game's secret and earn a fortune, he spent months on adventures without fruitful results.

For better or worse, Shura, Flynn's in-game character, ends up in a great Wyvern's den, acquiring a hidden class and a monstrous race. Join him as he defeats his past and paves his way into becoming a true legend in both worlds.