|Anime debut||Yu-Gi-Oh! GX episode 75: "Taken by Storm, Part 1"|
Thunder, known as Ikazuchimaru (雷丸) in the Japanese version is one of the four members of the Light Brigade led by Sarina, tasked with capturing Syrus Truesdale and Tyranno Hassleberry alongside Frost.
Thunder heavily resembles Joey Wheeler; his hairstyle is similar, but slightly toned down, and he wears similar clothes. He is a pale-skinned man with purple hair in a sporadic style, and long blonde eyebrows shaped like lightning bolts. Thunder wears a dark blue denim jacket over a white shirt, black pants, and sneakers. When first communicating with Sarina, he wore more traditional robes with a lightning bolt printed on his headband.
Thunder is more willing to use teamwork to win his Duels, and he is angered when Frost uses effects that could damage him. In the dub, he makes several storm and lightning puns.
The "Ikazuchi" portion of his name in the Japanese version is derived from the word "ikazuchi" (雷), meaning "lightning".
Thunder has electrical abilities; he can teleport from place-to-place in a bolt of lightning, and shock people into unconsciousness. He has control of the "Zaborg the Thunder Monarch" spirit that presided over the city during his Tag-Team Duel.
Thunder and fellow Light Brigade member Frost were called upon by Sarina to Duel Syrus Truesdale and Tyranno Hassleberry in order to lure in Jaden Yuki to test him. They kidnapped Solomon Muto and baited Syrus and Hassleberry to the top of a large building in Domino City. Unlike Frost, he was more willing to use teamwork to win and was angered when Frost almost caused him to take damage with "Reflector Bit". Thunder opposed Syrus, whose Machine "roid" Deck was at a disadvantage to Thunder's Deck. He oppressed Syrus with "Zaborg the Thunder Monarch", pushing him into a corner.
After they revealed that they intended to use Syrus and Hassleberry as bait to get to Jaden, Syrus orchestrated a comeback to make Hassleberry Thunder's opponent. Faced with Hassleberry's massively powerful "Super Conductor Tyranno", Thunder was forced to use "Lightning Talisman" to save himself, which damaged the other players, including Frost. He drew his copy of "Mirror of Duality" that Sarina had given him, but could not use it since his Life Points were too low, opting to discard it for "Monster Reincarnation". However, Frost himself played the same card and won the Duel, with Thunder losing all his Life Points along with their opponents.
Frost left Thunder on top of the building after taking Syrus and Hasslebery away, and Thunder was sealed in a card by Sarina alongside Frost as she no longer had any use for him. Thunder was seen in Kaiba Land's virtual world alongside the other Light Brigade Duelists, and he was released after Jaden and Aster Phoenix defeated Sarina.
Thunder plays a Thunder Deck, supported by Tag-Team Duel-exclusive cards. His tactics are less standard than his partner's in that he utilizes cards such as "Rampage Condenser" and "Lightning Talisman" to inflict damage through effects, rather than through battle. His primary card is "Zaborg the Thunder Monarch". Thunder also includes anti-Machine cards for his Duel against Syrus Truesdale.
|Syrus Truesdale and Tyranno Hassleberry||75-76||Win (with Frost); Eliminated|