I Was Reborn in Another World, But I Awoke Inside a Corpse

Chapter 129: The Maw Beneath the World

The gate beneath Yggdrasil opened like a wound.

It wasn't carved. It wasn't built. It had grown—like a scar twisting beneath the bark of the world. With every step downward, Isaac felt the mana change. Not fade. Curdle. The air grew thicker, heavier, as though his body were wading through invisible syrup.

Brynhildr walked beside him in silence, her expression grim, wings folded close like a cloak of judgment. She carried no spear this time. Only reverence—and wariness.

They passed through three sealing thresholds, each one etched in celestial script meant to bind whatever lay beneath.

All three were broken.

Isaac didn't comment. He didn't need to.

At last, they emerged into a vast cavern, where the roots of the World Tree throbbed weakly in the ceiling above. They were gray and withered—like veins running dry.

And below them, something waited.

The ground shifted.

No—not the ground.

The shape.

It uncoiled from the darkness like a serpent awakening from beneath a battlefield of corpses. Meat and rot clung to the stones, but the stench was far worse—not decay, but consumption.

A massive figure rose into view.

No disguise.

No illusion.

He appeared as he truly was.

Beelzebub.

The Sin of Gluttony.

A monstrous entity with a bloated, pulsating form—equal parts man, insect, and nightmare. His skin was a patchwork of stretched flesh and scaled plating, veined with black ichor. His belly distended and contracted like a living forge, each breath exhaling a cloud of foul mist that twisted into gnashing mouths and whispers.

A halo of fanged maws hovered around him—detached, hungry, whispering in ancient tongues that fed directly into the mind.

His face was obscured by a writhing mass of tongues and teeth. His eyes glowed with putrid green hunger, twin suns of endless appetite.

And when he spoke, the very root beneath Isaac's feet cracked.

"Another morsel. How bold… to walk into the belly of the feast."

Isaac didn't flinch.

"I'm not here to feed you."

Beelzebub laughed—a sound like bones snapping underwater.

"No… not feed. But perhaps I'll savor you slower than the others."

He reached forward, claws wide. The very air recoiled.

Brynhildr stepped forward, light beginning to rise around her—

But Isaac raised a hand.

"No," he said calmly. "He's mine."

Brynhildr paused.

The light faded.

Beelzebub tilted his head, grinning with one of his mouths. "You speak with such certainty, little system-born. Have you ever fought something that doesn't just want to win—but to devour everything you are?"

Isaac's eyes shimmered faintly with layered system code. His voice was low.

"Yes."

He took a step forward.

"I've seen your kind. I've erased your kind."

The air began to shift again—but this time around Isaac. Not weight. Not pressure.

Purpose.

Beelzebub's smile faltered.

Just slightly.

Isaac unsummoned nothing. Drew no blade.

He simply walked forward as if the laws of this abyss didn't apply to him.

"You've been feeding too long," he said softly. "Time to starve."

The battle hadn't started.

But the balance had already begun to shift.