Looking for this story I read a while back. MC originally is born to a noble family but his mother is a servant. He eventually gets away and starts cultivating. Ends up in this series of islands that become their own nation. At one point he studies magical beast and how to combine them with humans. He combines himself with the last of some sort of abys dragon. There's also and empire in the story. With the emperor having two high level disciples called left hand and right hand. Empire uses some small nation as a training ground and the mc helps them out. At one point a piece of a higher realm falls to this realm and all factions scramble for a piece. MC fights the head guy of his old family. Ring any bells?
Honestly just the bit about him creating his own unique cultivation technique, opposed to finding or being taught a cultivation technique makes me think it is an original story. I'm guessing you read this on a site like royalroadl or scribblehub.