Ten Thousand Souls Banner, Human Emperor Banner: The Protagonist Is Tricked into Cultivating Demonic Arts by a Golden Finger Demonic Cultivator Elder 万魂幡人皇幡。主角被金手指魔修老爷爷忽悠修魔

I once saw a book on Fanqie where the protagonist was tricked into cultivating demonic techniques by his golden finger, an old demonic cultivator. The old man told him that the Banner of Ten Thousand Souls was actually the Human Emperor Banner. Later, the protagonist successfully killed the demonic cultivator in retaliation. I can’t find it now. Does anyone remember the title?