Amulet of the Horsemen's Steed

A small amulet showing images of the apocalypse made of adamantium that is too small for large and bigger creatures and too big for a tiny creature to wear. As an action, a creature attuned to this item can summon a nightmare fully under their control. The nightmare shares their alignment and will only listen to the creature that summoned it. When the creature dies it is banished back into the amulet and can't be summoned until dawn the next day, it does not heal its' wounds naturally it only heals after it is killed and banished back into the amulet. The steeds' speed is doubled and it shares its' summoners' initiative but doesn't go until after them.

Notes: Requires Attunement by a Medium or Small Creature