Books in the Nineveh's Child series

They told me the world above was dead. They lied. It was their world that was dying.I escaped. Outside, I found a family, and I was loved. My new home had its struggles but it was very much alive.Six years later, Nineveh came for me. And nothing would stop them from trying to take me back...My brother told me about the post-apocalyptic wastes outside of Nineveh, a land teeming with genetically-engineered monsters and radioactive fallout. He was my only friend besides a cantankerous cat that haunted my room. But my brother spun tales to pass the time, and none of my teachers or doctors would tell me the truth about the world that was or the purpose of our life in Nineveh. My brother got sick. Other children did, too. The last thing my brother did was make sure I got out. Most of what he told me about the surface I found untrue. The real monsters were the ones who came for me and destroyed the life I had. So I would return to Nineveh, learn its secrets, and save my brother.But could I face Nineveh's greatest secret without losing my soul?But my old world hadn't forgotten about me, and it wanted me back, even if this meant destroying everything in its path to find me.