|Other language names|
|Anime Deck||Mobius the Frost Monarch|
|Anime debut||Yu-Gi-Oh! GX episode 75: "Taken by Storm, Part 1"|
Frost, known in Japan as Koorimaru (氷丸」 Koorimaru) is one of the four Light Brigade members and is called upon by Sarina to be Thunder's Tag Duel partner against Syrus Truesdale and Tyranno Hassleberry.
Frost is a pale-skinned man with blue eyes, short brown hair and a goatee, both with triangular edges, and two silver rings in each ear. He wears a grey beanie, a black fur-lined jacket over a maroon shirt, brown pants, and black shoes. When he first communicated with Sarina, he wore more traditional Japanese robes with a blue snowflake printed on his headband.
Frost is heavily condescending and competitive. In comparison to Thunder, he is heavily uncaring towards his partner, activating harmful card effects without regard for Thunder and even defeating him with Syrus and Hassleberry to win their Tag Duel.
The "Kouri" portion of his name in the Japanese version is derived from the word "kōri" (氷), meaning "ice."
In the English version, Frost speaks with a Hispanic accent in a "gangsta rap" style voice. He also commonly makes cold related puns.
Frost has limited ice-related abilities; he can conjure localized storms and teleport himself and others in contact with him in a whirling blizzard. He also froze Solomon Muto's bandanna solid to the point of being able to pierce concrete.
Frost and Thunder were sent by Sarina to lure in Jaden Yuki. They did so by attacking Solomon Muto, resulting in Jaden, Syrus Truesdale, and Tyranno Hassleberry in splitting up. He froze Solomon's bandanna solid and passed it onto Chazz Princeton to give to Syrus and Hassleberry. When Syrus and Hassleberry arrived on the top of the building, he and Thunder challenged them to a Tag Duel. Frost used "Side Attack" to force Hassleberry, whose Dinosaur Deck was at a disadvantage in comparison to Forst's Ice Deck, to face him, and Syrus to face Thunder. Frost quickly displayed his flippant attitude towards his partner when he brought out "Reflector Bit" to deflect Hassleberry's attack towards Thunder, though he claimed that he knew Thunder had his own "Reflector Bit" ready.
Frost brought out "Mobius the Frost Monarch" and pushed Hassleberry into a corner. When they revealed that Syrus and Hassleberry were being used as bait to get to Jaden. Syrus and Hassleberry made a comeback, with Syrus using "Dark Computer Virus" to face Frost and free up Hassleberry's field. After Hassleberry cleared the field and brought out "Super Conductor Tyranno", Thunder was forced to protect himself with "Lightning Talisman", which damaged Frost. Syrus brought out "Super Vehicroid - Stealth Union" and attempted to wipe out both Frost and Thunder at the same time, but Frost activated "Mirror of Duality" to defeat not only Syrus and Hassleberry, but also Thunder.
Frost transported to find Jaden, Solomon, and Aster Phoenix, informing them that he had their friends ebfore returning with Syrus and Hassleberry to Sarina and Chazz. He arrogantly pawned off their unconscious bodies to Blaze and T-Bone, and expressed his desire to Duel Jaden. Sarina condescendingly reminded Frost that he had barely defeated Jaden's friends and would be no match for Jaden himself, before sealing Frost into a card, declaring that she no longer had any use for him. Frost was seen trapped in Kaiba Land's virtual world alongside the other Light Brigade Duelists, and he was freed after Jaden and Aster defeated Sarina.
Frost plays an Ice Deck, supported by Tag-Team Duel-exclusive cards. His tactics are less upfront than his partner's in that he utilizes cards such as "Mobius Castle" and "Mobius Glacier" to weaken his opponents' monsters, then destroy them through the attacks of "Mobius the Frost Monarch".
|Syrus Truesdale and Tyranno Hassleberry||75-76||Win (with Thunder)|