"Indeed." The Abomination snarled at the memory of its humiliating defeat and exposed a row of white, pointy teeth made of Decay. "You broke me down into many small pieces but I had all the time I needed to rebuild myself.
"At that point, I just had to take the passenger seat in your life and wait for the right opportunity. Whenever you practiced your spells, I learned from you. Whenever your so-called children, my parents, passed their knowledge onto you, I learned from them as well.
"While you wasted your time playing family, I worked my ass off to find your weak points in both mind and body." The Vastor-Abomination's laughter was joyless, filled only with spite and cruelty.
"You should have wondered why over time controlling your Abomination half became harder to control instead of easier. It was because I was learning how to counter your will and replace it with mine.