Curse the Heart by Emily Blackwood

For Sinner and Athena, captivity is forever.

After their fight against the ministry ended in capture, the two are forced to move to the barracks, where they’ll live and train with the other claimed mystic pairs.
The only problem?
They never completed the claiming.
As two of the most powerful mystics, Sinner and Athena try their best to convince everyone their bond is complete, even as the truth seems to slip further and further away.
Only the claimed survive here.
And even that might not be enough.
As the deadly war games approach, their forged connection strains.
But something else simmers beneath the surface… something that connects them beyond the strength of any claiming.
Sinner and Athena never imagined claiming with anyone, let alone each other.
But options are running out.
Bond or die.
Unless it’s already too late…