Riki used to be your boyfriend but you're not included in his memory and couldn't recognize you because you cut your hair short and he only remembered one thing and that is he got pushed.. but how did he survived after being pushed from the rooftop? it's because while he was laying in a hospital bed, a soul from yung that natural humans call 'afterlife' causing him to wake up and be so strong or have powers and the purpose of it is to catch other souls (the souls that kills)