Why didn't the spirit just plainly state the state of affairs in the state that those two princesses of the state are stated to belong to? Rather than sending mc on a quest around the world like this.
It's simply poor story-telling for some of the apparently protagonistic characters to refuse to share useful information with other protagonistic characters.
@Oeconomist
On the other hand, this is one of the only isekai stories I've read that has a plot that looks like it'll actually go somewhere. Visit the four spirits, find the truth, beat up the big bad (maybe after a fetch quest), the end. As opposed to the usual "Wouldn't it be cool if {insert story gimmick}. And then this happened and this happened - [repeat excessively]".
Granted, it'd be a miracle if it actually happened that way, but at least it looks like it might.
This story has had various virtues and (in keeping with what you've written) potential virtues. Two consequences are that the issue about which I complained is more unhappy than it would be in an otherwise inferior work, and that I'll continue to read this series until and unless further short-comings accumulate too greatly.
(Chrissakes I hope that this series doesn't degenerate into yet another “harem” fantasy!)