Spring, Summer, Autumn (Fall) and Winter, each season has a set of NPCs including Harbingers named after that season, eg Autumn Harbinger, that give Daily Quests They can be found in each of the main cities, and at the north wall of the southeast corner of Archosaur They give quests for dig points and level 100 ??? Invader enemies that hit like soft pillows (163 physical) but have 72k HP and very high defense. Like the Crazy Stone and other quests, you can get a new quest on a given day even if you had one running from a previous day, and only just turned it in.