My Useless Brother is the World's Strongest Magical Girl?!

Five years after the Great Catastrophe, superpowers have become the new normal—but some things never change. Like my deadbeat older brother's obsession with his favorite idol. "Faith is everything! Money is temporary!" he declares while begging me for cash to buy limited-edition merch. When I refuse, he calls me a demon. Little does anyone know, this broke otaku hiding in his room is actually the world's most powerful magical girl hero. How did my family's biggest disappointment become humanity's greatest protector?