This line that he said in .Hack, was probably one of the biggest indications that he realizes his obsession with Haseo has to be held back/worked with. In fact he may be obsessed with Haseo, but he understand his obsession and understands that only if Haseo himself *depending on what you choose to respond with* reacts to his advances positively, should he himself show his feelings towards Haseo more. He doesn’t wish to control his relationship with Haseo, he wishes to move forward with Haseo for whatever is best for the both of them.(and yes he went a little crazy at their wedding if you got it, but he was letting his eccentric side out, and to get that wedding you had to have encouraged Endrance from Haseo) Endrance/Elk may have the flaw of being obsessive over people, but at least he learns how to deal with his obsession in a positive manner. THAT was his major character development, learning how to live with his obsessive nature around certain people who he cares too much about. Because you know what character development is? Learning about the flaws of that character and the character not changing who they are but rather learning how to live with their flaws, and move forward as themselves.
It’s worth mentioning that those lines weren’t even said to Haseo (though it’s fair to say he had Haseo in mind). It was addressed to Hiiragi, as a way of saying ‘look, Sakaki’s doing you no good so quit supporting him’. That’s another reason why it’s a good moment in Endrance’s development. He may appear to be one-note crazy over Haseo, but at times he’s quite aware of other people. He can be empathetic, as in Hiiragi’s case, or manipulative, as in Sakaki’s later on, and you can tell he’s considering how Haseo sees him, not just how he’s seeing Haseo.
'Sorry for saying something weird all of a sudden… Don't worry about it'
‘So you’ve come to like me this much…’
‘Yes…that’s right. I’m fine…I understand how you feel’
‘What exactly do you want from me…?’
Granted, there are plenty of times he just rambles about how great Haseo is, but it’s all harmless praise - ‘wow I’m so happy to talk to you’ rather than ‘hey bb is your real self as fine as your pc ;)’.
He talks about a deep fear of being alone, but rather than using that as an excuse to be smothering, holds himself back and makes it clear Haseo is in charge of how much contact they have. I can imagine him sitting hopefully at the computer all day, and if he doesn’t get any messages then he’s a little sad…but there’s always tomorrow. While it’s still not healthy to wait around like that (or say things like ‘my entire existence is to serve you’), he’s balancing obsession with a genuine respect for Haseo’s own wishes. He never gets impatient or acts entitled to more than he already has. Because while he really, really wants to be around Haseo, it’s important that Haseo also wants him to be there, that they’re both happy with whatever they choose to do.
I think keeping that balance makes Endrance a more interesting character, and it’s one reason the ship appeals to me. Despite his issues, he’s trying his best to be someone who’ll have a positive impact on Haseo’s life (regardless of whether he gets the ‘reward’ of returned affections or not). While the way he latches onto Haseo might seem a bit childish, Endrance is more mature than he sometimes gets credit for, and his attitude to romance is better than a lot of guys out there.
Conclusion: Endrance is obsessive, but in the nicest possible way, so it makes me love him even more. ‘Move forward as themselves' is a good way to put it, and I’m glad that’s what he tries to do, rather than erasing his own personality to look completely ‘normal’.