Avenging Angel by Tamsin Baker

The good went above, the bad went below. And those lost souls who could be pulled either way, well…that’s where I came in.
Gabriel is a Fallen Angel, sent to Earth for penance against his sins. He must save the souls of the Damned in order to earn his way back into Heaven.
Kadie, a half-witch-half-human is his charge. Gabriel must fulfil his oath to protect her – only he falls in love with her instead. Which is totally forbidden. And out of their time together, a child is born. A total miracle. Half Angel, Half Witch.
Only it’s not all good. Demons have tortured Kadie. She lies unconscious after giving birth. Poisoned and near death. Not even the power of three witches can awaken her.
Can Gabriel ensure the safety of his son, the life of his love, and defeat the Demons plans to invade Earth?