Dexter, known as Tenpei Hayano in the Japanese version, is a best friend of Luna, Leo, and Bob in the anime. An alternate version of Yu-Gi-Oh! 5D's Dexter appears in Yu-Gi-Oh! ARC-V.
Dexter has brown hair and eyes, and is not seen without his glasses. He usually wears his
Duel Academy uniform but when out of uniform he wears a white collared shirt with a red bow tie and suspenders, navy blue shorts, white knee socks, and brown dress shoes.
Leo went to the Daimon Area to duel the Black Rose. Dexter had modified his Deck specifically to duel against her. When he first meets Yusei, he was afraid of him due to his criminal mark, but began to admire him once Leo told him he had customized his and Luna's Duel Disks to fit them and was strong enough to enter the Fortune Cup.
Pre-World Racing Grand Prix and WRGP
Dexter has enlisted into
The New Domino City Duel Academy along with Leo, Luna and Akiza. He was in danger of being expelled by the vice-principal, Rudolph Heitmann, who despises them for having low grades and low- Level monsters. He is saved after Yusei defeats Heitmann in a Duel.
Later, he accompanies Leo and Luna into a supposedly haunted forest. Leo wants to turn back, but Dexter reminds him that it was his idea to explore the forest in the first place, and the group continues in. After Luna and Leo lose him (Leo was chasing after Luna when the latter fell into a trance), Dexter runs to
Poppo Time to tell Yusei what has happened.
He is also frequently seen in the stands along with his friends
Patty and Bob watching Team 5D's Duels in the WRGP.   
Yusei's duel with Z-one, he is seen cheering Yusei on.
His Deck is unknown, but he had once claimed to have built an anti-
Plant Deck to counter Akiza, though he had never dueled on-screen..
The only shown card from his Deck is "
During a school lesson, he was seen using a copy of "
Armed Samurai - Ben Kei".
Reverse of Arcadia
Yu-Gi-Oh! 5D's World Championship 2010: Reverse of Arcadia, Dexter uses a Fairy Deck titled " With Intelligence".
Over the Nexus
Yu-Gi-Oh! 5D's World Championship 2011: Over the Nexus, Dexter uses a Deck similar to the one from the from previous game titled " Angel Inside".
Yu-Gi-Oh! ARC-V episode 98: " Friendship Finale"
Yu-Gi-Oh! 5D's episode 14: " Bloom of the Black Rose"
Yu-Gi-Oh! 5D's episode 67: " Lessons Learned"
Yu-Gi-Oh! 5D's episode 70: " The Wicked Spirit"
Yu-Gi-Oh! 5D's episode 104: " Knight Takes Pawn"
Yu-Gi-Oh! 5D's episode 119: " The Impregnable Scrum! Crush the Unbreakable Defense!"
Yu-Gi-Oh! 5D's episode 125: " Soul Solution" ↑
Yu-Gi-Oh! 5D's episode 150: " Entrusted Feelings of My Father"
Canon Game original Downloadable World Champions Free Duel Free Turbo Duel Free Tag Duel
Creation Resonator, Barrier Resonator
Frozen Fitzgerald, Dark Diviner
Masked Chopper, KA-2 Des Scissors
Angel O7, Naturia Bamboo Shoot
Nurse Reficule the Fallen One, Fire Princess
Swift Scarecrow, Gallis the Star Beast
Terrorking Salmon, Terrorking Archfiend
Reptilianne Viper, Alien Kid
Formula Synchron, Shooting Star Dragon
Shien's Squire, Shien's Footsoldier
Harpie Girl, Amazoness Trainee
Demise, King of Armageddon, Evigishki Soul Ogre
Elemental Hero Prisma, Gem-Knight Emerald
Mist Valley Baby Roc, Blackwing - Jin the Rain Shadow
D.D. Scout Plane, D.D. Survivor
Dragon Queen of Tragic Endings, Crystal Beast Sapphire Pegasus
Moon Dragon Quilla, Sun Dragon Inti
Free Turbo Tag Duel
D.D. Trainer, Unicycular
Sonic Duck, Sonic Chick
Mad Sword Beast, Abare Ushioni
Gilasaurus, Super-Nimble Mega Hamster
The Legendary Fisherman, Shark Cruiser
Diskblade Rider, Chaosrider Gustaph
Stygian Sergeants, Stygian Street Patrol
Reaper on the Nightmare, Dark Blade the Dragon Knight
Harpie's Pet Baby Dragon, Blackwing - Zephyrus the Elite
Supply, Elemental Hero Flame Wingman