Meadow Greenlee They mentioned that he had a half-brother before. Could it be him? That was the first person I thought of.
K-Gorgeous I have no idea who the 'arch nemesis' is. Since the blurp says that he's 'back' I'm assuming that it is someone that has already appeared in the book's before. If not, I speculate that it might be someone that is the arch nemesis of the Malachai. As for the eye of Ananke if you read Instinct you"ll know that it's a stone that is used to see the future.
Sandhya If you really want to read instinct, just go to eBooks.com and search with the authors name, apart from Invision, all its preceding ones are available for download, ofcourse you will have to buy it.....but it was well worth it. Loved every page.....good luck