Forgotten Manhwa name

Help me find the name pls guys. The mc (Yeom?) reincarnates into a novel where he is roommates with the future demon king in an academy. Mc has purple/blue hair and becomes romantically involved with him while trying to avoid death flags (by preventing him from transforming into demon king). Eventually he dies from this huge spider monster and reincarnates back into the world again, but as the hero (blond) destined to oppose to DK. Turns out that this guy has already reincarnated many times in different people trying to kill the DK, but he forgets after he dies each time. They reunite, sign these oath things to suppress their urge to kill/attack each other, and try to do damage control I guess. Sorry if that was hard to follow :)