What purpose would Marluxia even have in KH3?

[Shimmy 458]

I get what you're saying but again it literally doesn't matter because both Marluxia and Saix were plotting to overthrow Xemnas the leader of the Organization and offing fellow members along the way for that cause. That in itself is traitorous no matter what actions both guys used. 

 

My main point wasn't necessarily the nature of their betrayals (although I felt like it's nice acknowledge) but rather their difference is personality. Saïx was desperate, defensive, and confused. Marluxia is self aware, prideful, and narcissistic. This marks him as a prime candidate for northood but not guaranteed. 

From what we've seen so far from how the possession works, you either gotta be willing (Braig) or at insecure state (Terra and Riku) . Saïx's circumstances are ambiguous but what's canon is that he didn't know everything that was going on and Xemnas and Xigbar played him like a puppet. But from what we know of Marluxia is that he's not insecure at all, heck he's oozing self confidence and his nature of betrayal just furthers this. So that means if Marluxia becomes a nort he'd have to be willing which he's not above doing seeing as how he's power hungry and I wouldn't put it past him to sell his soul for a keyblade. However his pride might prove to be an issue because it's hard to see Marluxia the rebel who fought against a leader who promised him a heart and gave him a home simply because he felt he was better willingly submit. It's possibly- but not guaranteed. Also I forgot to mention this before, but Heavy Metal Sailor Moon over there was possessed before his betrayal ever happened (yellow Orange eyes in days, pointy ears) meaning that his entire scheme was in vain. It seemed like Saïx's fate was planned from the beginning, Marluxia however is fair game and can go either way. 

We can't rule out Marluxia for being a traitor, because Saïx was one too, however if anything does prevent him from being a candidate I'm placing my bets on his personality. Xemnas did refer to a traitor from being ruled out as an organization member but we can't automatically assume he was referring to Marluxia. Definitely a possibility, but not guaranteed because Marluxia's got a shot to sign up for northood. 

Of course this is just going off of what has been establish already and this series's plot can do whatever it wants and I'm just speculating. I'm definitely not ruling Marluxia out as a possibility-heck I want him to be a nort and he's got the potential to be one. I just think he's not guaranteed. But eh that's just my interpretation.