Abyss ( character ) Abyss is the final Number ' s Guardian that appeared in the " Yu - Gi - Oh ! ZEXAL " anime . He is a mighty sea god and the spirit form of " " , entrusted with two Mythyrian " Number s " within an underwater temple . He later tests Reginald Kastle in a Duel to revive his original memories and inherit both " Numbers " . Design . Appearance . Abyss is fittingly similar to his card form , without the helmet . He has sky blue skin which is adorned by blue armor slashed with gold . He wears a gold headpiece on his forehead - set with an aquamarine - colored stone - and has black hair and a beard arranged in a similar way to Shark ' s hairstyle . Abilities . As a spirit of a " Number " , Abyss possesses great power . He is capable of possession , shown when he did so to Rio Kastle . Similarly , he is also capable of saving Nash and Marin and sending their souls without their memories into Reginald and Rio Kastle , who had recently died in a car accident . Biography . History . Vector offered a blood sacrifice to Abyss in order to receive aid in the destruction of the United Lands of the Poseidon Ocean from the latter . As a result , Abyss laid waste to the city and killed many of the Kingdom ' s soldiers . Marin offered herself as a sacrifice afterwards to revive and purify Abyss of Vector ' s control . Later , during Nash ' s attack on Vector ' s lands , Abyss aided Nash in fighting Vector ' s army . He was Summoned in Nash and Vector ' s Shadow Game . After Nash and Marin were trapped in a dark dimension by Vector , Abyss rescued them ; offering to send their souls to Earth at the expense of their current memories , where their souls were transferred to Reginald Kastle and Rio Kastle after the latter siblings were killed after a car accident . Yu - Gi - Oh ! ZEXAL . When the Different Dimension Airship neared the undersea ruins , Abyss called out to Rio Kastle , who was on - board . He was eventually able to influence her enough to get her to jump off the ship . Shark , Yuma Tsukumo and Astral followed . They tracked Rio to the temple and were led through a maze , where they were separated . Shark reached the heart of the temple , where he found Abyss possessing Rio . Abyss claimed that he and Shark were destined to fight and urged Shark to " awaken " , as he would inherit Abyss ' power . Shark agreed to Duel and Abyss gained a great advantage through " Gorgonic Guardian " . He proceeded to show Shark visions of his past life , when he was the king of the United Lands of the Poseidon Ocean Abyss insisted that just as his past life lost his sister , he would lose her here too , due to the weakness in his heart . Ceasing his control over Rio , she fell a great distance , but was caught by Yuma . Abyss then entrusted " " , the second Mythyrian " Number " tied to the ruins to Shark and told him to defeat him and reclaim his memories as the king who led the world . After his defeat , Abyss admitted to Shark that he was following orders from his past life to restore his former memories before disappearing , leaving his " Number " card to Shark . Deck . Abyss uses a ' " Gorgonic " Deck while controlling Rio Kastle , focused on ATK reduction .