Here's a question I've been mulling over and would love to get your opinion on! Is it sad that Stanley sacrifices himself for Xeno's happiness without seeming to consider that his own absence might hinder that happiness at least to some degree? Is it sad that the first thought he has when he's depetrified again (if I've got the mental order of out-of-context manga panels right lol) is that he's been brought back for a specific mission (true, but he doesn't seem to even consider that he could have been brought back as a reward for Xeno or anything like that).
You and I generally talk and joke about them being VERY MUCH an established couple, and that's definitely my preferred interpretation, but I feel like this could be spun into an argument against that, or at least against them being on the same page about how much they mean to each other? Or am I just pulling angst out of the thin air because I think it's fun? 😅
We don't actually get any of Stanley's thoughts on the matter (ever). They wake him up, they talk to him a bit, but he doesn't actually say anything other than answer a technical question and agree to do the job. And the next time we see him is similarly no-internal, action only (and it has nothing to do with Xeno).
What we mostly get from Stan is a lot of quiet observation of the situation, checking over Xeno to see if he's okay/healthy/happy/not being coerced, and then agrees. So much of their interaction in that scene was pretty shadowed/private even from the audience that it's hard to read too too much into it. I'm really excited to see if the anime gives us more on it.
At no point in the manga is it ever mentioned that Stanley is brought back for Xeno (just a brief interlude that emphasizes this is important to Xeno emotionally), and Xeno gives him a number of emotionally charged gifts afterward that further underscores that.
I do think this, and the scene where he sacrifices himself, are a big part of the "Stanley Pines while Xeno doesn't even understand" interpretation, and I get that. I'm not going to say it's not a fair interpretation, even if it's not My Preferred One.
I do think it's fair to point out that science does matter a lot to Stanley. Not just Xeno, although of course Xeno, but Xeno would not respect him or have shared power with him if Stanley did not respect science. He's not a scientist, but he mentions using Xeno's "science" when he settles in to snipe Senku/Taiju. Xeno mentions that he would make Chrome a commander (which is what Stan is!!!) because he respects science, even if Chrome is not particularly skilled (yet. He's very talented, he's very good, but he is missing a lot of basic skills yet).
And when Stanley sacrifices himself, he's mostly thinking of Xeno, but he does also mention that Xeno will be continuing science. Because it makes Xeno happy, but it also seems important to Stanley that science continues. Possibly because Xeno Infected him.
He doesn't say he thinks Xeno will be happy. He says Xeno will continue sciencing (which yes of course is an important part of Xeno's happiness. But).
Do I think Stanley was underestimating how much he meant to Xeno...hm. You know, when I read the Viz translation, I thought, absolutely not, how could he be a hostage to get Xeno to agree if Xeno didn't care about what happened to him. So I checked the Japanese to reinforce my argument, and the Japanese Did Not (RIP me), although it didn't disprove it either. Could justifiably go either way.
Do I think Stanley is the kind of person who would sacrifice some of Xeno's happiness for his health, despite how devoted he is to Xeno's happiness?
...You know, I think I kind of do think that.