Staying in the Background

Ren Cambell wakes up in the GX universe. However, why should he need to get involved with the plot? Everything is going to be fine anyway if he stays away from the main characters, right? He's just a background character in this world. He's got a second chance to live his best life. Become a pro duelist, get a girlfriend and get rich off card games. Wait... Who's that other guy?