Anos Voldigoad originated in the Mythical Age, born an orphan under tragic circumstances when humans killed his pregnant mother, causing him to emerge from her corpse. This event shaped his core perspective and motivations. He rose to power during intense conflict between demon factions, humans, spirits, and gods. Establishing the castle Delsgade and uniting demons through overwhelming strength, he earned the title "Demon King of Tyranny" due to his ruthless rule against enemies. Despite this reputation, his actions aimed to protect subordinates and end perpetual warfare. Growing weary of conflict, he orchestrated a pact with the hero Kanon, Great Spirit Reno, and Goddess of Creation Militia, sacrificing his life to separate the world into four distinct realms using the Beno Leven barrier, hoping time would heal racial divisions.

Reincarnating 2,000 years later, he was born a hybrid demon to parents Gusta and Izabella, retaining memories of his past life. Shortly after birth, he aged himself into a child form for convenience. His current parents provided affectionate support, contrasting his orphaned origins. Receiving an invitation to the Demon King Academy, he further aged into adolescence and enrolled. During the entrance exam, he demonstrated unparalleled power by overwhelming pureblood rivals like Zepes and Leorg Indu, reviving them repeatedly after lethal force. Despite flawless academic performance, the academy branded him a "misfit" due to historical inaccuracies naming Avos Dilhevia as the true Demon King.

His personality blends absolute confidence with a defined moral code. He values loyalty, rewarding followers like the twins Misha and Sasha Necron, and prioritizes protecting family, friends, and subordinates. This protective instinct manifests severely against threats, such as his brutal punishment of the pureblood teacher Emilia for endangering his mother and fan club—killing her and cursing her to eternal reincarnation as a low-status hybrid. Though perceived as tyrannical by enemies, he avoids unnecessary killing and fosters growth in allies, advocating for bonds of love and strength of character, ideals stemming from his own childhood devoid of family. Post-reincarnation, he exhibits cluelessness about courtship, accidentally engaging Misha Necron due to misinterpreted ring-giving traditions.

His capabilities center on the "Source of Destruction," a unique core nourished by death and destruction, amplified by his traumatic birth. His immeasurable magic power is routinely suppressed to prevent universal destruction. Even using a fraction of his power, he overpowers fused deities and manipulates celestial bodies like moving the moon. Physical attributes include lifting castles, halting collapsing skies, and moving faster than light. Key abilities include:
- **Magic Eyes of Chaotic Destruction**: Alters universal laws and negates fate manipulation.
- **Bebesd**: Interacts with and destroys the "source" (core existence) of beings.
- **Egil Grone Angdroa**: Uncontrollable inferno merging creation and destruction deities' power, threatening multiversal annihilation.
- **Venuzdonoa**: A demon sword that erases concepts, laws, and realities, summonable only near Demon King Castle Delsgade.
- **Revival Magic (Ingall)**: Resurrects within three seconds of death, though philosophically questioned as cloning.
His sole vulnerability is Evansmana, a holy sword designed to permanently destroy his source, though he survived an accidental strike due to the wielder's non-lethal intent.

Following reincarnation, he investigated historical distortions about his identity while confronting new threats. He temporarily assumed the alias "Anosh Portikoro" as a child during the Selection Trial arc to infiltrate royalist conspiracies. He also discovered memory gaps regarding Militia's sister Abernyu (Goddess of Destruction), later revealed as Sasha Necron. His journey involved reconciling allies' reincarnations: Misha as Militia, Sasha as Abernyu, and Lay Glanzudlii as Kanon—fulfilling their ancient hope of friendship.