Cant remember a manhwa(or manhua?)

So there was a manhwa or manhua i cant quiet remember, i tried to find it but i couldnt so this is my last hope :'D It was a bl manhwa or manhua. It was about a guy (mc) who had kind of special powers and there was a king i think he was some kind of a demon and mc was a human. The demon was lack of emotions so he tortured the mc, and k*lled mcs father at some point(?) at the end mc d*ed and reincarnated to back in time when he was younger. The king had a child form, when he was in child form the mc and the king met for the first time again and the guy helped him in a different way, at his first life he helped the kings child form with magic i think? But in the second life he treated him with herbs and stuff so the future changed and king kind of become a better guy. The mcs father wanted to study something like medicine i suppose? There is a spesific scene i remember, the mc learned that the child he was helping for years was actually the king because king was using a spell but spell failed somehow. Since the king tortured him in his past life he hated the king so he was shocked. I think the ling tried to get closer to him but then mc tried to k*ll himself so king gave up. Then king wanted a child from mc via some kind of egg(?) I dont quite remember this part either. I know it is not really possible to find but if anyone knows this manhwa or manhua i would really appreciate it :'D