For trivia pertaining to this monster's Number, see Forum:"Numbers" Xyz Monster Trivia. Any contributions regarding this type of trivia should be placed there, instead of this page.
- This card is the first monster to be Summoned through Chaos Xyz Evolution in the anime.
- Part of this card's Japanese name Hope Ray is an alternative wording of "Ray of Hope".
- This card's effect is related to its name due to the fact that it can only be activated if you have 1000 Life Points or less, providing a "ray of hope" in bad situations.
- This name is also a pun on the card's title; the Katakana for "Rei" can also be interpreted as "Rei", Portuguese for King.
- This card was the first "Number C" monster.
- Being the first "Number C", this monster was also the first Warrior-Type "Number C" monster.
- Also, this card was the first alternate form of "Utopia" like many of the protagonists' ace monsters, such as Yugi's "Dark Paladin" and Dark Sage, Jaden's "Elemental HERO Shining Flare Wingman" or any of his Neos fusions, and Yusei's "Majestic Star Dragon", "Shooting Star Dragon" and "Shooting Quasar Dragon". This card is Yuma's evolutionary Xyz Monster.
- This is the only "Number C" form of "Number 39: Utopia" that can be summoned through a non-Rank-Up method.
- This monster is Summoned via an alternate way of Xyz Summon, Chaos Xyz Evolution, similar to Jaden Yuki's use of Contact Fusion as an alternate way to Fusion Summon and Yusei Fudo's use of Accel Synchro Summon as an alternate way to Synchro Summon.
- This card is the first Xyz Monster to use another Xyz Monster as its Xyz Material.
- It is also the first Xyz Monster to name a specific monster needed for Xyz Material.
- It is also the first Xyz Monster able to be Xyz Summoned using only one Xyz Material.
- This card's effect is the opposite of its counterpart; the effect of "Utopia" is used to defend, while the effect of "Utopia Ray" is used for offensive purposes.
- This monster appears in the artworks of "Number Return", "Grave Chaos", "Xyz Revenge Shuffle", "ZW - Asura Strike" and "ZW - Leo Arms".
- This monster has the most appearances of any "Number C" monsters.
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