In Adventure Mode of Hyrule Warriors, sometimes this message pops up:
[Character name] is behaving suspiciously! Act quickly!
What does this mean, exactly? When I defeat the character in question, it usually says, "You foiled the enemy plan", but I don't remember ever seeing a consequence when I just ignore them.
On the regular adventure map, this appears to be happening in most (if not all) missions where you have to defeat a given number of enemies as quickly as possible.