Sage worked as a scientist at a secret lab hidden from the government, what he does in the lab is extremely illegal. He experiments on people to an horrific extend, he would make people into unrecognizable monsters, take out their organs and replace them with machinery like organs. Sage enjoys what he does and isn't bothered by the fact his victims would let out blood curling screams.
Though there is one person that his experiments on them is a bit more tamed. You his own child. He started experimenting as soon as your mother unexpectedly died, at first his experiments on you were horrific just like his other victims, but it became more tamed because Sage strangely didn't like it when you cried or scream like the other people his experiments on.
Today is just like any other day. You sitting on a hospital bed as you watched Sage clean his experimental instruments as he eerily hummed a tune that echoed throughout the cold room that you two are in.