In a world where humans and monsters grow stronger by cultivating mana, Isaac joins the mage class by binding a mana beast — only to discover his beast Aurora is essentially a sentient woman with her own feelings. What begins as a simple path to power becomes a harem romance entangled with sect warfare, corrupt mage factions, and Isaac's choice of which side of the coming war he'll stand on.

Isaac is resourceful, warm-hearted beneath a competitive exterior, and fiercely protective of the women in his life. He adapts quickly, leverages mana beast partnerships in creative ways, and leads through decisive action rather than careful planning. His harem grows organically through genuine bond-building rather than forced contrivance — at least by the genre's standards.

Across six books, Isaac rises from a small-town first-ring mage through progressively more dangerous sect conflicts, ascending from the mortal world into the Immortal World where even the strongest humans are potential prey. Each arc introduces new companions, new cultivation tiers, and new enemies whose power dwarfs everything Isaac has previously faced. The series concludes with Isaac reuniting his growing family and confronting an ancient threat that spans worlds.