From BZPB Wiki

The Kanohi Daran is the Mask of Confusion. There is currently only one in existence, which belonged to Kakamu. It was left in inter-dimensional space when Kakamu's armour was destroyed but was later found by the Fellowship of Kakamu, who placed it in the Realm of Shadows to store along with another artefact belonging to Kakamu, the Guardian Fire Spear.

Kakamu managed to find a way to duplicate it, so both he and Trantoshen could have one. Confusingly, the one that Trantoshen now wears is Kakamu's, and the one that Kakamu wore when he was a Turaga belonged to Trantoshen. The duplicate has now been destroyed, leaving Trantoshen's one the only one remaining.