I had killed Levin. The truth struck like a knife in the dark, tearing deep into my heart. I had made the mistake of treating Levin like the Apostle of Fire and believed he would survive. But he was weaker than that demon, and vulnerable due to the extensive damage to his soul he had just recovered from. Furthermore, he had allowed my mana to penetrate him while I healed him, which, when combined with my experience with his soul, allowed me to devastate his mana on a scale I had only begun to approach with the apostle. It was the difference between stabbing someone with a toothpick and a sword.
I too worried about modifying Link Ability and healing Korra to notice his soul never stabilized, but continued its path to destruction. I should have been more careful. I should have realized what would happen. I should have–