I want an isekai scenario where a guy meets a goddess and is given a mission to bring peace to a war torn fantasy world. Start it off with "I died."
I died. I was just trying to get home from shopping after school. My sister asked me to get something extra for dinner, so I stopped by the store. On my way out, a man came sprinting at a little girl with a knife. I didn't think. Before my thoughts caught up to my actions, I had a knife in me. I didn't last until the ambulance even arrived. I closed my eyes, breathed my last breath, and was suddenly standing before a woman in robes. She was so beautiful I couldn't even look her in the eyes, not from embarrassment but because if physically hurt. Her voice echoed through my skull. "Boy, I will grant you a single wish, but you must fulfill a mission. If you accept, I will grant you a sliver of my power to take with you on this mission."

I tried to ask what the mission was, but my voice didn't come out. She read my thoughts directly. "You must bring modern peace from your world to the world of Tahssent, a world of elves and demons and dwarves and war."

"What do you mean?" I thought, and suddenly information flooded my mind. This sudden information download into my brain hurt. Tehssent was exactly as the woman said. There was magic, feudal kingdoms, various races, and wars. She wanted me to bring modern peace to a place like this? 

"Will you accept?"

I knew the other option was to simply be snapped out of existence. My wish would be to return to when I died and survive this time. I would do what she asked and make it back to my world no matter what it took. If she was giving me some of her powers, I was certain I could make it happen. 

"Very well, boy. Do not disappoint me. I'll be watching," she said, pointing a finger at me. 

The next thing I knew, I woke up in the middle of an unfamiliar city. The sounds of voices and horse drawn carts echoed on the wind. I had been reincarnated to a new world.