Fugitives of Chaos | John C. Wright
Raised in a strict British boarding school, five orphans--Amelia, Vanity, Colin, Quentin, and Victor--discover that they are not truly human, but rather have been kidnapped from their real parents, robbed of their powers, and raised in ignorance by a variety of super-beings, and now they must learn to control their individual unusual abilities in order to escape. Reprint.