- Diesel 10
- Spencer (sometimes)
Hiro is wise, very dignified and enormously kind. He is friendly and is able to find good in any engine he meets. He does not appear to hold a grudge; in his first appearance, he helped Spencer after an accident, despite Spencer previously trying to send him to the Smelter's Yard.
Hiro once lived in Japan, therefore having a slight Japanese accent. He was the strongest engines on his railway, and he was famously known as the Master of the Railway. He was eventually brought to Sodor where he worked for many years. However, he began to show his age, and the works did not have the necessary parts to repair him. To escape from being scrapped, he was hid in a siding, waiting for parts from his homeland. However, the parts never came, and Hiro was all but forgotten.
Eventually, Thomas found him and, fearing that Hiro would be scrapped if he was not Really Useful, promised him to restore him to his former glory while keeping it a secret from Sir Topham Hatt. Thomas had many of his friends help him in the restoration, and Hiro quickly gained their friendship. After breaking down again after trying to escape Spencer, Hiro was hidden away in another siding, where passing engines visited him and kept him company.
When Sir Topham Hatt found out about the situation, he ordered Hiro to be sent to the Sodor Steamworks where Victor over saw his restoration. Once Hiro was repaired, he helped Spencer after his accident and together with Spencer and Thomas, helped finish the Duke and Duchesse's Summer House. After though, Hiro got homesick and missed his old friends terribly, so Sir Topham Hatt arranged to send Hiro back to his homeland.
Hiro did come back to help with all of the summer holiday traffic in Season 13. He also told Thomas how to properly transport the bee hives to Farmer Trotter, which he promptly ignored. He also told the other engines what to do when he thought that Sir Topham Hatt was too busy, only to become "Master of the Muddle".
Hiro is still on loan to Sir Topham Hatt, known as the Fat Controller. He shunted Henry to the Steamworks to have his side rods repaired. When he became homesick, Thomas brought him to Misty Island, which reminded Hiro of his home.
Later, Hiro and Henry took on some bad coal while transporting trucks to Brendam Docks. Henry didn't want to continue, but Hiro kept puffing. Diesel tried to show Hiro to be rough to the Troublesome Trucks, but Hiro refused. As a result of this, Diesel caused Hiro's milk churns to spill twice over the Far Controller!
In the Eighteenth season, Hiro stopped Caitlin from taking Thomas's coaches and almost had a collision with Toby at Knapford Junction.
- The Biggest Present Of All
- Buzzy Bees
- Hiro Helps Out
- Henry's Health and Safety
- Emily and Dash
- Happy Hiro
- Fiery Flynn
- Calm Down Caitlin
- Henry's Hero
- Percy's Lucky Day
- No More Mr. Nice Engine
- Thomas's Tall Friend
- James In The Dark
- Toby and the Whistling Woods
- Kevin the Steamie
- Wonky Whistle
- Race to the Rescue
- Express Coming Through!
- Ho Ho Snowman
- Flash Bang Wallop!
- Thomas and the Rubbish Train
- Thomas Toots the Crows
- Sodor Surprise Day
- The Lost Puff
- Away from the Sea
- Togo Igawa (UK/US)
- Hiro's theme is "Mecha Green Hill Zone" from Sonic Chaos for the Sega Game Gear & Master System.
Counterparts (boy version)
WARNING: You may add appropriate counterparts. But, do NOT delete any.
- Old Rusty (TUGS)
- Shamus (Theodore Tugboat)
- The Cuckoo Clock Master (Dastardly and Muttley)
- Master Splinter (Sonic the Hedgehog)
- Zizzer-Zazzer-Zuzz (Dr. Seuss)
- Pip (Animaniacs)
- Grandpa Boris (Rugrats)
- Mr. Hyunh (Hey Arnold)
- Danny (Phineas and Ferb)
- Scott (Total Drama)
- Mata Nui (Bionicle)
- Zeekeeper (Super Mario Bros.)
- Blizzard (Donkey Kong Country)
- Master Pu (Kablam!/Action League Now!)
- Manny (A Bug's Life)
- Doc Hudson or Shu Todoroki (Cars 1 & 2)
- Tiny Castle Knight (Nitrome)
- Akira (The Simpsons, both are Japanese)
- Adventure Man or Master Mantis (WarioWare: Portfolio Cartoon, the Latter is Old)
- Junichiro Hill (King of the Hill)
- Toshi (American Dad)
- Legendary Fordman (Vehicles)
- Father Christmas (Noddy's Toyland Adventures)
- Lucario (Pokemon)
- Frostini (Chuggington)
- Root Beer Tapper (Wreck-It Ralph)
- The Chronicler (Spyro the Dragon)
- Hoot Loop (Skylanders)
Counterparts (girl version)
- Flora (Thomas the Tank Engine & Friends)
- S.S Vienna (TUGS)
Counterparts (Villain version)
- Diesel 20 (Thomas the Tank Engine & Friends, fan-made)
- ? (TUGS)
- ? (Theodore Tugboat)