This is the part in my story "The Wraiths" where the lead villian, Ambrose Whittemore, loses control of his body over to a malevolent monster.
Galen had finally caught up to Ambrose, who was holding a piece of the Sintflut Key. He could see that Ambrose was pale, bleeding from multiple cuts all over his body.
"Ambrose, you don't have to do this. You can still fight the Wraiths!" Galen pleaded.
"Don't you get it, Galen? I cannot rebel, I cannot resist, I cannot fight back; my will is not my own anymore! I am just a puppet for their leader. This is all I can do..."
"If you set the last piece of the Key, you'll open up a portal to the race that maintains our existence, and you'll get them slaughtered! Do you want that?"
Ambrose's face twisted in pain, his grip on the piece was shaking even more.
"This... isn't about what I want, it's what they want. The Wraiths want the Helgen anihilated because they are responsible for their creation. The Wraiths were made into powerful beings, but in the process, were made into monsters. Don't you see? They won't stop until every last Helgen is dead! I have no choice in such matters!"
"Ambrose, you were a hero. You fought to save others, not harm them. You were always the strong one. You can fight this!"
Ambrose broke free from his control, and dropped the key to the ground. He faintly smiled at Galen...
"I'm sorry, Galen. I always was--"
"You are of no use to me anymore, human," a sinister voice boomed.
All of a sudden, Ambrose's cuts began to bleed more severely, and his arms began to move erratically. Ambrose then pulled at a bit of his arm, harder and harder, until the flesh began to rip. As he continued to tear at himself further and further, he cried out in pain and surprise. He drove his fingers into his mouth, and ripped at the cheeks. The gleam of steel could be seen under his flesh, as he continued to rip himself apart. Soon, the man that was once Ambrose Whittemore was now a tall, imposing skeleton with three glowing eyes...
"I... Am... Revenant..."