The Convict's Refusal. The Aethel Chronicles, #1

Kael has three rules for surviving Neutral-Row: never eat the meat on a Tuesday, never make eye contact with the patrols, and never stay somewhere long enough to have something to lose. He breaks all three on the same day. When a Viper raid tears through the market and a gap-toothed boy ends up alone behind rain barrels, Kael does what he always does - puts himself between dangerous people and someone who can't afford to be in their way.
It costs him a net over the head, a Cobra arrest, and a cell in the Obsidian Spire. It also costs him Lyra. She's his jailer. Cobra Interrogation Lead. Professional blank where her face should be. A violet birthmark hidden behind her left ear - the same mark the clans call contamination and Kael knows means something else entirely. She has a twelve-year-old brother in a Re-Education camp and a Councilor named Aldric who owns them both.
Kael has a grandmother's lullaby with a forgery cipher in the third verse. What starts as a desperate bid to survive becomes something larger than either of them planned: a hidden network two centuries in the making, a device that can undo the Oath of One Blood at its source, and an ancient war that never really ended - only went quiet and waited. The Convict's Refusal is a fast-paced dystopian romantasy about a man who can't stop noticing things he shouldn't, a woman who has been performing loyalty so long she's forgotten what the real thing feels like, and a twelve-year-old boy who survived six months in a Re-Education camp by deciding, with complete deliberateness, not to be diminished by it.
The enemies-to-lovers slow burn is real. The world-building has teeth. The lullaby means something. For fans of Fourth Wing, An Ember in the Ashes, and The Cruel Prince.