I Transmigrated into the Book as the Protagonist's Father from the Start

Unfazed by spears and armored cavalry, my iron body was forged in a mountain of corpses and a sea of blood! Wielding my halberd, I strike across thirty thousand miles, and armies flee at the sight of my white robes! I slaughter until none in this world can match me, then ascend to stand level with the heavens! Heaven weeps and the gods grieve, all trembling before me. I alone am invincible in this world!

This is the legend of a mighty overlord who roamed the Myriad Worlds, leaving a tale of his dominion behind. On that day, the sky was filled with the corpses of gods, and the cries of the immortals echoed across heaven and earth.