Hmmm, we could just shove it away as "oh, friendship", but depending on Urana-sensei, it might be actually an interesting conflict - Zodyl vs Rudo, I mean. Not because it's "friendship" vs "no friends" though.
1. Zodyl's mindset is "focus on the goal, do everything to achieve it, never lose that focus and don't even look for anything else". In a way, I feel like he wants Rudo to understand and join him, feeling they might share a goal here. He feels like he understands Rudo, but still, our boy reaches a different conclusion. Zodyl probably sees it as inferior, because the original goal Rudo had was completely different.
Basically, what I imagine Zodyl to think: "You little coward. No, you're not greedy, you've just backed out of your own goal and set it to something easier. You pussy boy, you".
2. I LOVE THAT for Rudo though. You might feel that's quite a jump from how hell-bent on revenge against the Angels he was, listening to Amo's story. I don't think this desire is gone though. I just feel like living his life in peace and happiness is more important here. If he can do both, he will try to. If only one thing - we know what he chose. That's development.
3. Oh, also - what made Rudo shift (or at least shift more quickly) was seeing Zodyl's cold, calculated attitude. Like "oh, I can become like him, if I'm still this feral little raccoon boi". And he doesn't like what he sees in Zodyl. They're each others' mirrors, each mirror showing what could've been... but also what CAN BE in the future.
4. I know it's a bit meta now, but Zodyl fulfilled his role perfectly so far with how he presents himself, how he's intimidating people with words etc. He's yet to show us what can he do with his hands though. So far, we only know that he can easily beat Jabber up and it's still just from Jabber mentioning it. You might disagree, but it's important for a villain (in a battle series, at least) to hold his own in a fight. Whatever Zodyl vs Enjin entails, I hope Zodyl just manages to draw. It's important, IF we want him to stay being a danger in the future.