My Cthulhu-Style Path to Immortality

[Takes off after 20 chapters! Cthulhu + modern cultivation + twisted history + mildly warped + fantasy + slow-paced, expansive worldbuilding] In an age beyond reckoning, the “source of cosmic filth” descended upon the starry realm of the present world, crashing into the River of Time. Towering waves overturned all of history, and time itself grew murky. What had once been a normal history became distorted, spawning countless eerie, filthy entities. The sages of every age fought back against the corruption. Two of the four rulers of the present world were annihilated by the “source of filth.” As time moved toward the final battle, could the Chaos Dao Venerable and the Eternal Silence Black Buddha, after laying their plans for ten thousand years, keep the present world from being corrupted?