Invincible from the Moment I Summon

A good-for-nothing youth finds a blood-red rune glowing in his palm. At death's door, he can summon an ancient demon wyrm to slaughter his enemies, but the strain on his spiritual power makes him cough up black blood. Just as everyone thinks his body is about to explode, Peng Yao, the holy maiden of Medicine King Valley, takes his trembling hand. "Let my spirit soul be the catalyst, and I'll help you form a pact with twin divine phoenixes!" From an ordinary mortal body to the pinnacle of the divine realm, he crushes a holy scion's skull with his left hand while diagrams of divine and demonic formations that can shatter the void swirl at his fingertips. When world-ending thunder rolls from beyond the ninth heaven, a hundred thousand divine-realm powerhouses watch the young man standing atop a black dragon pull out a bronze bell. "Don't rush. I've still got eight hundred Demon Venerables I haven't released."