Poison Dragon: The Legend of an Asura
Hmmmm i can't decide if I like it??? I mean i might like it after a few more chapters but somethings about this manhwa irks me off. Jin jakang is the sole survivor of the medicine sect massacre and was experimented upon by the poison sect because he gained poison immunity by eating the red centipede which was used to kill everyone in his sect. He then escapes but gets trapped in a mine with other fallen sect members and comes out alive after 8 years. He's the only one left. Now he wants revenge.
Nano Machine
Cheon yeowoon is the illegitimate child of the demonic cult leader and his mother was poisoned to death when he was young. While being chased by enemies, someone from the future appeared and injected a nanomachine in his body hurriedly and disappeared. From then, his quest to become the lord and get revenge for his mother begins
The Villainess's Road to Revenge
Sand and Song of the Seas