My Sister is the Grand Supreme

Iris and Lyra are sisters from an ordinary mage family. Unbeknownst to Lyra, Iris is the legendary Grand Supreme, her power sealed and hidden to protect them from Abyssal threats. Lyra's dream engagement to Dylan, heir of the Fire House, shatters when he publicly humiliates her, aided by the prodigy Chloe. Witnessing her sister's despair, Iris unleashes her dormant stardust magic, defeating Chloe and stripping Dylan of his power in a shocking display. Iris then reveals the truth: Lyra possesses the ancient Wind God Bloodline, the key to defeating the Abyss. Together, the sisters awaken this power, expose Dylan's betrayal, and survive relentless assassination attempts at their academy. They ultimately unite to thwart the Lord of the Abyss's invasion, with Iris ascending as the revered Grand Supreme and Lyra growing into a mighty Wind Magus, forever each other's strongest ally.