I think it's worth observing that Eli as a character had an established backstory and principles even before Victor while Victor's whole character and narrative predominantly revolves around Eli and going against him. Even during Lockland, he found a way to make himself the main focus of Eli's project, twist his thesis into their thesis. He forced himself onto Eli's narrative, made himself the main focus. While Eli's 'kill all EOs because they are an affront to God' was because of what he experienced with Victor and their falling out, he was still more independent a character in terms of purpose. And then there's Victor on the other hand whose whole purpose in the first book was to kill Eli. It's so fascinating and is also incredibly funny considering Victor is the main character.