The time when games and reality mixed, the story about skills

One day, everyone on earth heard a voice, one simple sentence that changed everything, "*Cough Cough*, I'm uh... is this on? ... Oh! Yes! Hello! I'm your new overlord, your old one is gone, and because I'm in charge now, I'll start a game for my own amusement! go to any of those shops..." as he said that, lightbeams rained from sky and hit every major city, where a mysterious new building now stood, blended in like it'd always been there. "to begin!"