Astral

"'I was sent to Yuma's world for a mission but I don't remember what it is!' — Astral to Yuma in 'In The End, Part 1'."

Astral,"Original Number", is a mysterious visitor from another world of existence who serves as the main protagonist alongside Yuma, who is the only one who normally hears and sees him. Astral's memories are scattered in the form of the 99 "Numbers", and so far a total of 50 Numbers, with the addition of one Chaos Version. He was sent to Yuma's world with a certain mission, but he forgot his mission due to his oblivion. He normally resides in a special world within Yuma's Key, featuring a vessel whose parts become unlocked as Astral collects more "Numbers" cards.