Spoiler!
Kim Dokja will be the strongest at the end while fighting with Nirvana.....dokja plan something to kill nirvana.....at the end dokja dye the scenario is to kill the strongest.....by dokja death scenario will end and dokja revive himself and kill the Nirvana.....At the end Nirvana endup in the 4th wall of the kim dokja and becomes the part of it.