[ Desperation certainly fits. It's a concept Claude's familiar with in more ways than one considering how it can spur things forward when used productively or tear them apart at the seams when not. He's gotten the sense the nations here have been on the brink of war for so long that embracing long lost rituals meant to turn the tide would seem reasonable. It'd explain a couple things, like -

Claude doesn't finish that thought to himself because the mention of Summoned from years ago stops that line of thinking before it's really started, and so does the idea of what might happen to those who vanish. There's a long moment where he doesn't say anything at all and simply studies Kyle. Maybe it's appraisal, maybe it's simply a chance to consider both weighty statements, or maybe it's just that it feels fitting. He doesn't bother to clarify while picking up his own threads to follow. ]

If Solvunn reveres the old gods so much, who's to say those gods weren't once the first Summoned here? In some part, anyway.

[ Farfetched as it might sound, Claude's serious. It could be possible. It'd be far too close to Rhea if true, but maybe that's not the first time it's happened in history elsewhere. Further explanation might come in a minute after suggesting this first. ]

Especially if we're assuming there's a possibility of those who vanish didn't just... return home as assumed but remained connected here in some way as we must be now. I've heard of Summoned who were once here before, left, and returned. Depending on how the summoning process works then maybe Time isn't so fond of being played with.

[ Never mind the questions that raises about what that means for him, his friends, and their own accounts of what they've lived, specifically. ]