Mid-season, artefacts appear in Natar treasure villages. Attack with your hero from a village with a treasury and win, and the artefact is yours; it activates after a while.
Small artefacts affect only their village, large and unique ones your whole account. Types: construction and training speed, troop speed, storage, cranny, building durability (mason), scout strength and seeing incoming troop types (eagle's eye), great storage and the jester artefact whose effect changes randomly every day.