“What I'm about to do now is a good old-fashioned monster hunt,” Izaya said, using the excuse that he had arrived at after considering dozens. “Maybe if I beat him, I'll finally feel like I'm a human being.”
By eliminating Shizuo, Izaya might be able to see himself as a human being.
All the exaggerations he had ever made might become truths.
When Namie or Shinra got snarky with him, he might be able to sincerely reply, “Of course I love myself. I am a human being, after all.” It felt strange, but he even considered it worth risking his life for the sake of that one stupid phrase.
I don't know. These two quotes kind of sum up so much of what Izaya deals with for me. Izaya talks a lot, but at the end of the day, he's only human, but he can't even feel that way. He's doomed to be an outsider who can only view the world from the outside.