MTL - Make You Happy - Chapter 312 juvenile

In a Fantasy world in which a young girl with the Divine Protection of the Hero battles against the Demon Lord. In that world, Red, the elder brother of that young girl Hero, possessing the Divine Protection of the Guide which only grants a high initial level, fought in the initial party of the Hero.

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

Seven days remained until the countdown to genetic mutation.Seven days later, all creatures on Earth would undergo mutations. Giant mutated creatures would swarm and attack humanity, putting their fate in jeopardy. The entire Earth would be ruled by these mutated beings!Yang Xiao accidentally walked into a genetic store where various gene potions were sold, capable of altering human body functions.From that moment on, he embarked on a crazy journey of genetic evolution.