The one who trusted learned to find good in all things, even those things that were hated by all else. He would conquer fears of insects, realizing that without them, there could be no flowers. He learned to understand that everyone, even those who were evil had reasons, backstories to how it happened. No one was evil just because. Even the concept of death was no longer a harsh one to this being of good.
The one who killed fell deeper and deeper into despair, seeing the ugliness of the universe in even things of beauty. She saw things such as love as just two people pretending, or even forcing attraction so they two could benefit from the situation. Things considered most beautiful, like the birth of a new being, was just another sign of stress for everyone around it - nevermind that it was a new being who would soon know the suffering of a world with no defined meaning to it.