Curious, seductive, and popular, Hiro is always ready to go on an adventure. He is a faithful friend to Ren and Koichi, and would never hesitate to put himself in danger to help them out; however, his appetite for risk and adventure can sometimes lead him into complicated situations. He falls under the spell of the mysterious girl in the club and by accepting a diamond-shaped object that appears to be more attractive than dangerous he leads his friends straight into the trap of tobacco.