Astral

Japanese name:

アストラル

The "Original Number", Astral is a mysterious spirit from another plane of existence, Yuma Tsukumo who is the only one who normally hears and sees him. A calculating person, Astral makes a list of his observations of Yuma and other human behaviors while offering his dueling wisdom to the boy in order to obtain the 99 "Numbers" Cards which are actually fragments of his memories which got scattered when he entered Yuma's dimension. It is thanks to his tuition that Yuma gradually becomes more skilled and experienced as a duelist while maintaining his positive outlook on life. Yuma and Astral's partnership is shown to be one of equals, though: from Yuma, Astral learns to be more positive and in touch with his emotions. He normally resides in a special world within Yuma's Emperor Key, featuring a strange ship whose parts become unlocked as Astral collects more "Numbers" cards. However, Astral is horrified to learn that his purpose is to destroy the world. Eventually, this is revealed to be a deception by Number 96 which turns out to be a corrupted memory known as a Forbidden Number. His true purpose
as mentioned by Eliphas and later confirmed by Astral himself, is to destroy Barian World.

Voiced by: Miyu Irino (Japanese), Marc Thompson (English)

Wiki