Thanks to the broken-up nature of the splash art text, the translation is also more broken than usual with the app's Lens translate...
"Yome / wife /
Shijou / history /
The last day (or 'Let's go') / The strongest."
And I find it a bit silly Nasa hasn't realized just how badass his wife is, but I guess sometimes you have to have these things spelled out, like just how competent she is as a fighter. How physically strong she really is. She doesn't need a protector, she needs someone to keep her company, and soothe the pain of loneliness she's had to endure. And ultimately help her find a solution to her plight, too, but the loneliness is the more immediate thing he can help with just by spending time with her.
And that must be why it's virtually impassible in winter, heh... And also probably why Chitose was trying to climb in, since that's likely the only other way to get around that obstacle.