Now, the interesting dynamic of his behavior is if he shifted from being entirely self-centered and self-serving.. To trying find meaning in life that isn't exclusively himself. Be it saving the world, screwing over the plans of a Prince, or even making life just a lil better for someone else..
Like, idk, the last bit doesn't even need to be romantic, just some ill conceived notion like "I want to save him" or "I just want her to smile again" or even "I just want someone to remember me" You can still be selfish without being self-centered on your goal
Who knows, maybe Arellius and Nora could bond over how they both wish to protect Niralie, like a sword and it's shield
) it makes sense why she would butt heads with Arellius so much(or even Grelok, when appropriate. Just bc your a thief doesn't mean you have to steal. Pay for the damn apple!) However, and as much as Nora would serve as a predictable target to undermine*, I honestly have always seen it that Eolwyn is more so his aligned rival(morally & objectively speaking) Which makes sense when you think about it, both stand on opposite spectrums but arent too far off from one another. And unfortunately, Niralie has more than proven she's not the moral counter-weight to Arellius, since she too has a fair bit flaws that can lead to disastrous results(I'll touch up on this more jn a bit. Just wait) 
The only thing to her favor is that bit can go both ways, and she herself may have an influence on him 'bc we've been through so much' i.e softening up his harder edges, and in turn, maybe find some closure for herself
)