It was first mentioned when the Emperor's Key turned off, and the voice of The Door told Astral that the promised time has come to obtain ZEXAL, a power which can turn all the darkness into light. Later, the Door reappeared to Yuma and gave him the power. When Yuma obtained it, he and Astral were combined. Interestingly, they were combined the same way as monsters are overlaid during an Xyz Summon, which they call it "ZEXAL Morph" ("Xyz Change ZEXAL" in the Japanese version, エクシーズ・チェンジ・ゼアル Ekushīzu Chenji Zearu).
When the combination was completed, Yuma realized that his appearance had completely changed, as he was wearing an armor that gave him a golden aura, and had given him golden hair and one golden and one red eye. In this form, Astral was sharing his body. Using its power, Yuma can perform a "Shining Draw" (シャイニング・ドロー Shainingu Dorō) and create "ZW" (Zexal Weapon) monsters. He obtained "ZW - Unicorn Spear" to help "Utopia Ray" defeat Kite's "Galaxy-Eyes Photon Dragon".
The power was later used in Yuma's Duel against III. After combining with Astral, Yuma drew "ZW - Phoenix Bow" and equipped it to "Utopia Ray" to destroy "Number 6: Chronomaly Atlando", allowing Yuma to defeat III and claim victory.
- This is the second game mechanic used to fuse two characters into one; the first one would be Jaden Yuki using "Super Polymerization" to fuse with Yubel, though the second instance is not as permanent.
- So far, Yuma has not used this ability on Earth. He first used it in the world inside the Emperor's Key and in the doorway to Barian World.
- ↑ 1.0 1.1 Yu-Gi-Oh! ZEXAL episode 22: "The Shark Hunter"
- ↑ 2.0 2.1 2.2 Yu-Gi-Oh! ZEXAL episode 24: "Hunting Down the Hunter, Part 2"
- ↑ "Yu-Gi-Oh! ZEXAL episode 49: "Crestfallen"