The Octagram hall grew completely silent as all eyes turned toward Diablo.
Rimuru Tempest looked at his subordinate with calm curiosity and asked, "Diablo, what do you know about the Ancient Evil God?"
Diablo bowed elegantly. "I know a little, my lord. I shall share everything I know — every detail."
Guy Crimson leaned forward, his crimson eyes sharp. "Can you tell us everything? Leave nothing out."
Diablo nodded once, his voice smooth and ancient as he began to speak.
"The Ancient Evil God is the most powerful being among all gods. He was not born from nothing. He had a father — the Supreme Ruler of the Celestial Realms — and a younger brother. In the beginning, both brothers were good and loving. There was no evil in their hearts. They lived in perfect harmony under their father's rule.
But one day, the father gathered all the gods and goddesses and, in front of everyone, appointed his younger son — the weaker of the two — as his successor and the next ruler of the heavens.
From that moment, the Ancient Evil God changed.
The betrayal and humiliation turned his heart black. He declared war on his own father and brother. He rallied his loyal subordinates — a legion of fallen angels and dark deities — and began a cataclysmic war across the Celestial Realms.
He was too powerful. Many gods and goddesses fell. Countless angels were slaughtered. The celestial realms themselves were nearly destroyed — entire divine domains shattered and cast into the void. No one could stop him. Not even his father, the Supreme Ruler, could match his growing strength.
In his rage and ambition, the Ancient Evil God obtained the power of an Entity Being — a forbidden existence that exists beyond the laws of gods and mortals. Once he achieved that, his father could no longer restrain him.
In the final battle, the father used every last ounce of his life force to seal his eldest son away. He tore the very fabric of the Celestial Realms apart, creating a prison in the endless void that would continuously suck away the Evil God's life force for eternity. The father died shortly after completing the seal, his body and soul exhausted beyond recovery.
That is how the Ancient Evil God was imprisoned… but he was never truly destroyed."
Diablo paused for a moment, letting the weight of the story settle over the silent hall.
Then he continued, his voice growing even more solemn as he explained the being's abilities.
"As for his powers… they are beyond what most gods can comprehend. He can grant subtle yet terrifying gifts to those he chooses — skills that grow without limit, hidden from the eyes of the Goddess of Light. He can twist fate itself, interfere with summonings across worlds, and plant seeds of chaos that bloom over centuries. He is the embodiment of rejection and defiance. His influence can turn the discarded into something unstoppable. Even now, sealed in the void, he can reach across realities and offer his power to those who have been thrown away by the light."
The Octagram remained utterly silent, every Demon Lord listening with rapt attention as Diablo revealed the dark, ancient history of the one being even they had never fully understood.