Noboru Kodo is Gao Mikado's classmate at Aibo Academy, initially presented as arrogant and temperamental, easily annoyed especially by nicknames like "Kitten" or "Cat-shirt" referencing the tiger design on his clothing. He possesses yellow eyes and yellow hair with black tiger stripes. His early attire includes a pale yellow shirt with a black tiger symbol, blue jacket, orange shorts, blue sneakers, and tiger-striped accessories. Later, he wears a white t-shirt with a golden tiger symbol, a sleeveless blue vest, red scarf, grey capris, blue loafers, and retains his wristbands.

Originally ranked second among Aibo Academy's sixth-grade Buddyfighters, he wields a Dragon World deck. His initial buddy is Dragon Knight, Red Baron. After losing to Tetsuya Kurodake and accepting guidance from El Quixote, he replaces Red Baron with Dragon Knight, El Quixote. His core gadget is a lance, and his fighting style evolves to incorporate dual-wielding lances or swords. An early character arc sees him overcome underestimation of his abilities and gain self-confidence through Buddyfighting, defeating criminal Aooni Konmae and resisting bribery during the ABC Cup. His family moves to America, leading to a temporary departure before he returns to lead Team Destiny in the Gaen Cup, aiming to support Gao against the Disaster threat.

During the Hundred season, Admiral Skull Knight Gratos brainwashes him into serving as an "Inverse Fiend" named "Tiger," using a Dungeon World Knight deck featuring Knight of Glory, El Quixote. Freed from mind control, he retains the Dungeon World deck. Later, in the GGG Cup, he adopts an Omni Lord Knights deck.

A significant transformation occurs in Triple D when he accidentally ingests a Gender-Change Pillball tossed into his drink by Samuel Nakaoka, resulting in a permanent gender change. This leads to ongoing comedic interactions where Samuel calls him "Melitten" or "Nekonyu" and grabs his chest, provoking physical retaliation. The change shocks his friends, while Samuel conceals his responsibility. Earlier in Triple D, a separate temporary gender change occurs when Tetsuya accidentally provides him with a women-specific workout regimen.

Throughout his journey, Noboru evolves from a jealous rival into a dedicated ally, maintaining rivalries while demonstrating loyalty. His Buddyfight record includes victories against opponents like Genma Todoroki and James Knightman, and losses to figures including Tasuku Ryuenji (as Purgatory Knight) and Gaito Kurouzu. His relationships emphasize growth in courage and self-acceptance, particularly through his bond with El Quixote.