AleXander

Alexander Silver (sometimes called Alex and Xander to differentiate the two bodies when they're in the same space), is the product of extensive magical experimentation. The pair represents two halves of the same soul, which has been magically split into "two" people. He is, in essence, the same person in two places. This is also how he views HIMSELF, as both halves share thoughts, emotions, and even memories. 

Alexander's original self was kidnapped and used for experiments meant to combine magic with technology, as well as create artificial in-humans (monsters) to be used as foot soldiers, and a variety of other tasks during a war. 

The first experiment was done to see if there was a way to bolster the number of available test subjects by "splitting" them in various ways. After which both halves would be used for different tests based on the individual differences that resulted from being separated. 

"Alex" ended up being the sicklier of the pair, but his body contained the sum of all the magic the original soul possessed. It was decided he would be used for experiments regarding magic, and especially the boosting of one's natural power and affinity for spell casting. Because there isn't really a way to grow a soul's magical abilities other than time and study, they ended up finding a way for Alex to "pull" more energy from his surroundings in order to increase his power, but it does come with the threat of magical recoil (spell casting that damages the user). 

Xander, being the more hardy half (and with no magical abilities left), would be used to create another monster for the army ranks. He became an artificial werewolf. Essentially he has the properties of a werewolf's ability to transform and grow in size, but because he never came in contact with a real werewolf, he is unable to curse others, making him safer for the scientists to handle. His transformations are painful and bloody, and often don't occur CORRECTLY (think joints facing the wrong way, limbs being unusable, etc) because he is not a true werewolf. Because his body struggles to change, he was augmented with artificial joints and a spine, as well as a few other innards, to make the process viable without killing him.