My name is Shen Jin. I'm a seasoned office worker from Blue Star. One day, I worked overtime until dawn, opened my eyes, and found myself in the body of a high school student with the same name.
Good news: Everyone in this world awakens a superpower at eighteen. Everyone is a walking superhero.
Bad news: I awakened an F-rank power called [Calamity]. Literally, it means it'll be windy today and rainy tomorrow.
The whole class laughed at me. "That's hilarious. You're just a human weather forecast!"
Me: Laugh it up. The harder you laugh now, the more sincere you'll be when you beg me to make it rain a little less.
Then later...
A beast tide breaches the city, and all of humanity trembles in fear.
I stand atop the city walls and quietly open the System panel: F-rank Calamity -> SSS-rank World-Ender.
Beast Emperor: "You humans only sent a weather forecaster?"
Me: "That's right. Today's forecast: the beast race will be wiped out."
The heroine is the number-one ice queen at our school, reborn to protect all of humanity.
She looks at me coldly. "Can you control your Calamity? Don't hit our allies by mistake."
Me: "Don't worry. Precision strikes, beast race only. I won't freeze you."
I, Shen Jin, speak for myself: the ultimate calamity for all humanity, and her personal weather forecaster alone.
P.S. The System says that if my power keeps evolving, even "human extinction" will count as a natural disaster. It advises me to take it easy.