Spoiler

Novel it's fully translated but I don't remember names. Check at novelupdates. It's long and painfull story. I can try answer any questions you have

Pls spoil me a lot, like what will happen to their relationship, does anything big happen or a plot twist, how is the ending do they end up together

They will just get more and more in love but bc of MC health ML will be controlling and scary, like keeping in basement doctors crazy. At the end MC will get healthy, he will get his memories from previous world, ML also.

Thanks

Hold on wdym the ml too.. Like what’s written in the novel?

its been hinted that ml might be the hyung the mc was talking about in his past life, that might be the answer

OMG??

Yep, in novel it's not that obvious but in manhwa in flashback to MC's senior there are similarities to ML. In new world ML is just few years older, just like MC had sister but she transmuted in new world to being boy.

Founded Novel, https://springofromance.com/chapter/di-ch-1/