Battle Game in 5 Seconds (anime)

Battle in 5 Seconds After Meeting (出会って5秒でバトル, "Deatte 5 Byou de Battle") is a Japanese anime series based on the manga of the same name by Saizou Harawata and Kashiwa Miyako.

Plot
It was just a usual morning. Shiroyanagi Akira, a high schooler who loves games and Konpeito (Japanese sweets), has suddenly been dragged into a battlefield by a mysterious girl who calls herself Mion. The participants are told that they are "erased from the family register, involved in an experiment, and gained certain powers."

Akira is determined to win the game with his newfound powers and destroy the organization. Armed with a power no one expects and his "brain" skills, the new period of intelligence battle of begins!