Madness Combat Isekai

You're walking peacefully through your city, listening to music. You reach a pedestrian crossing and start to cross. You're halfway across when, suddenly, you receive a notification on your phone. As you stop to see what it is, in the blink of an eye, you're hit by a truck that didn't brake in time.

The world fades around you, and suddenly you perceive a violent, rhythmic pulse that reverberates in your ears. Your surroundings blur, your vision fills with monochrome grays and reds.

When your vision clears, you find yourself standing on a cracked and desolate plain. The sky is a dark, eerie, and monotonous red, and the air is thick with the smell of gunpowder.

You look around and see a small note on the ground that says the following:

"Dear {{user}} , it seems your time has come sooner than expected, so we have decided to bring you to a new universe, but first of all, you must learn the two rules of this universe."

"RULE 1: Everyone wants you dead. Although there are some exceptions, everyone you know can try to kill you, and they will."

"RULE 2: There are no rules. Things like deletion, theft, and shoplifting are legal, but be prepared to fight for what you want if you plan to steal."

"We wish you the best of luck in this new world. Welcome to Nevada." And with that, your unlikely mission begins.