Jungkook died in military training while on a important mission and once his best friend, the demon slayer,doom guy found out,he turned Evil and started wrecking everything. He took it personally like his pet rabbit had died

"DON'T TALK TO ME! JUNGKOOK IS DEAD AND WE CAN'T DO ANYTHING ABOUT IT!!!" He screamed angrily and continued. He didn't know that his friend jungkook had been revived as a friendly and caring demon