The Masks of Under Books in Order

The Masks of Under is one of Kathryn Ann Kingsley's big dark fantasy series, the kind built on world rules, layered power struggles, and a heroine who begins at a crushing disadvantage. Under is a place where magic defines everything. Everyone belongs to one of six ruling houses. Everyone has power.

Everyone except the heroine.

That lack of magic is what makes her vulnerable from the start and also what makes her dangerous in a world obsessed with rank, bloodlines, and control. Once her weakness is exposed, Under stops being merely strange and starts feeling openly predatory. Every interaction becomes political. Every fascination carries a cost.

Aon, the king of the House of Shadows, is the great dark pull at the center of the series. He appears in dreams, hides behind a mask, and carries the exact blend of menace and allure Kingsley readers tend to expect. The attraction between them is intense, but it is always tangled up with survival. If other houses discover the bond, they have every reason to use it, break it, or kill for it.

That ongoing tension shapes the full series. The books move through court politics, house rivalries, changing magic, and the widening consequences of a connection that should never have formed. Even when the romance takes up a lot of space, the world around it never disappears. Under is too unstable, too strange, and too hungry for power to allow that.

It gets larger as it goes.

This is a good fit if you like portal fantasy, dangerous kings, and a long arc that slowly opens up the history and rules of a very specific magical world. Start with King Of Flames and keep reading in order. The later books pay off threads about loyalty, identity, power, and what it means to survive in a place that was never built to protect the weak.