• I think I finished a quest, but there’s no portal! •
Different quests have different requirements. Your best bet is to read the Quest Objectives and to follow them. If you’ve followed them, and the screen has no enemy units and you’ve collected all treasure chests, then try marching your troops around the map. There are times where players may have missed triggering an event (such as bandits jumping out of the bushes when you get too close). Some events can not be triggered by flying units, and flying units can’t collect treasure chests.
If all else fails, surrender the quest and please post about it in the appropriate topic of the Quests forum and we will fix it as soon as possible. Please report quests that you were able to finish but have similar problems as well.