Apostasy - I C Lawrance - Bog

Felix and Silas knew the Tower. It was evil.
For as many years as they remembered, the constant hum had been the background of their every waking moment. They felt the muffled cries of misery that emanated from the structure. Cries of loss and longing, indistinct and ethereal yet still poignant and terrifyingly real.
It held the inhabitants of the Bowl in servitude. Taking what it wanted ... taking what it needed. The best anyone they could hope for, was to be left alone. But that now seemed a lot less likely.
As a child, Mortella had been endowed with natural beauty; fiery brushed-bronze hair, emerald-green eyes, and flawless complexion. These were gifts not to be squandered and it had served her well, but now she had been summoned back to the Tower.
Curtailed by The Presence and commissioned by The One, Mortella must succeed for The Black to be regained. Fail and ... well ...
Mortella, Felix and Silas knew that failure was not an option. Their Blood was the key.