The Wandering of an Unstuck Stepbro: Multiverse Travel Novel

A truck collision—or perhaps the protagonist's collision with a truck—propels him into Ryoto's body, the step-sibling of Rito and Mikan Yuuki. The world transforms into something dreamlike with anime characters inhabiting reality alongside mortals, yet no preparation exists for the moment a system notification disrupts class: [PING!][New quest][Mission: Finish the exam first and execute the Bully Maguire dance through the hallway.][Reward: 100 SP, shop feature unlocked.][Fail: Become emo Peter for one week.]…Perfect.