At long last - after decades of wait - Casca is getting herself cured! Her mind is probed into and her mental hang-ups are being dealt away with from within. It's pretty great. And yet... something feels wrong.
It's taken so long to get here, the resolution is just about bound to feel anti-climactic no matter what you do. For all the time it's taken, the big emotional stakes, Guts's driving force as it's been, there's been almost no narrative build-up or tension to it in all these years: no great climactic battles to power through, no emotional catharsis, just a couple standard wayside trips and fights with no particular personal stakes other than simply surviving. And then once we do get there, the king of the fairies pretty much immediately and with no additional fuss allows her to be healed.
The closest we've gotten to personal stakes is the nagging uncertainty on whether such a thing can work out at all, as well as Skull Knight's cryptic comment that what Guts wishes may not be what Casca wishes, something that was never really elaborated on - I mean, why would she not want to have her sanity restored? So it's mostly been a straight line, drama-wise (even if that straight line's been pretty high up).
I think it's the extremely long timespan that's throwing me off: we've been at this for so long already that one's mind begins to look forward to the end, and thinks the long-awaited climax is here. But this isn't it. We're not even close to done - it's just a quick break, a moment of healing after a long battle, nothing fancier than that. We're not in Mount Doom, we're in Rivendell.
And even then, as we see from the next volume, we're far from done.