Inhuman is about horrible experiments on human beings, with a secret hint towards Geralt Of Rivia who is also known as The Witcher at the end of the song.
lyrics
Injection forced into the skin
Green mass disappears inside
A horrendous experiment
No human feeling left alive
Trapped inside this hole
Delusions appear before his eyes
A vile putrid fate awaits
While emotions are cast aside
Liquid toxin starts to boil inside
Bone structure changing form
Deformed until mutation complete
Destined to be a killing machine
Abandoned by those who once loved, left alone
Locked into a cell
Unconscious but yet awake
A sick morbid transformation
He can’t but give in
His memory erased, created to protect this place
Not to be recognized
Shaped as the white wolf
Gen successfully been mutated
He now has been awakened