[@Xikari chan] An egocentric villain that believes that they are the sole success of the newborn experimentation project. 

This villain wants more than plain chaos; they want requital for the experimentation they suffered as a child. They blame their suffering on 'the world', and thus take out their angst on 'the world'. 

However, this villain is much more strategic in their gain of vengeance. This is because they are sane, unlike most of the other products of the experiments. As a byproduct, their morality is quite nebulous.

This villain would get a lot more character development (I would hope) than your average, one-dimensional villain. 

Shadow could learn about the experiments of her past, Galaxy could get closer to Shadow, and everyone gets development. Perhaps this is the story arc in which Galaxy dies, too.

Idk, tho.
What do you think?