Amulet

The Amulet was a gift to Emma from Mujika at the end of the Promised Forest Arc when the two said their farewells. It is key to the Cuvitidala Arc and later the Seven Walls Arc.

Appearance
The Amulet is a small necklace with an eye-shaped pendant. Its shape mirrors the designs of the Cuvitidala, indicating its connection to it.

Use
The Amulet is implied to be a sort of key to the Cuvitidala, allowing Emma to access the Day and Night through it.

Mujika
Mujika is the first known owner of the amulet. It is as of now unknown where she obtained it and why; however, she expresses knowledge of its purpose when giving it to Emma.

Emma
Emma was given the amulet by Mujika and uses it to enter the Day and Night at Cuvitidala and meet with the for the first time.