Soul tiara

The soul tiara was an unobtainable item that would have been created at the soul altar by using a blank tiara on the altar while also having a soul talisman in your inventory. As the blood altar did not exist at the time of its release, it was not made available.

With the release of the soul altar in Arceuus on 7 January 2016, which does not require a talisman, it was removed from the game.