He just change the terrain like it was nothing. Is he a literal god now?
Jokes aside, I don't get why putting up mountains around their capital is suppose to "warn" them.
More like, dude, you're doing them a favor by turning their city into a fortress instead.
Yeah sure there's only one entrance, but at least it creates a choke point where they can concentrate all of their defenses in one spot instead of being too dispersed around the capital. The Zweeden king must be cumming his pants in joy right now.