From the Start, I Was a Black Tortoise, and They Mistook Me for the Ancestor of the Mystic Sect

A slow-burn clan cultivation story. The protagonist's soul transmigrates into the Tianyang Continent, where he helps the Ye family rise to power and becomes its guardian divine beast. You say your bloodline is noble? Sorry, I have a divine beast bloodline. You say your cultivation reaches the heavens? Sorry, I grow stronger whenever my clan members cultivate. This blurb doesn't do it justice, so head to the story itself.