As an apex predator, Felix had quite the good battle instincts. Cats were normally very good hunters in the wild. But the domestication and the passing time made them lose that edge as they transformed into fluffy cute rolling balls of blobs. They were just like dough.
Felix was like that as well, he had a nice life on earth as Tsuru took care of him, but after he came to this world, things changed.
Ever since he became hungry and food wasn't near him, the instinct to hunt awakened and evolved inside him.
As he gained intelligence, things took a turn for strangeness. He couldn't adapt to society really easily, and he looked at everyone as if they were not beings.
He was also selfish and did whatever he needed to survive.
He was a special being, but he had no goal.
He was like a lonely boat drafting on the stormy sea all by itself.
He was a person with friends behind his back, but he didn't acknowledge them.