Shade's Children: Garth Nix

This was a futuristic Sci-fi book for teens. In the near distant future all the adults over 14 disappear and the children are rounded up in buses and taken to camps. In these camps they are kept alive until their 14th birthday when they are then "harvested"- their organs are used for making creatures/ machines, that then hunt escaped children. There is a group of children who have escaped and are being led by a scientist, but the scientist is not actually alive. He has somehow trapped his subconscious and can move between machines. The children he recruits for his plot to overthrow the overlords (who are in charge of the "meat factories" where the children are turned into machines)all have special abilities supposedly created by the "change projectors". Golden eye can see a little into the future, Drum can shape shift, Ella can conjure weapons out of thin air, and Ninde is telepathic. Ninde and Gold eye develop a relationship and are betrayed by Shade and given to the overlords. Drum and Ella escape and try to destroy the "change projectors". About the time Ninde and Gold Eye are being drowned, Drum and Ella are able to shut off the power destroying all the creatures and overlords(and we never really know why or how they became overlords)and freeing the children. Gold eye and drum use their powers and send a vision to Drum and Ella right before they die from the radiation. Gold eye sees the future where he and Ninde have two children who they name after Drum and Ella. That is the last thing Drum and Ella see before dying.