Hiro is a very old and wise Japanese tender engine, who used to be known as the "Master of the Railway". He was one of the first steam engines to arrive on Sodor.
Before he began working on Sodor, Hiro used to work on a railway in Japan. He was the strongest engine on the line, and was known as the "Master of the Railway". He was later brought to the Island of Sodor, and became the first steam engine to work on the island.
Hiro worked on the railway for many years, but he began to show his age, and overtime he began breaking down. The workmen did not have the necessary parts to fix him, so he was left on a siding until new parts from Japan could arrive. The parts never came, and Hiro was forgotten about and left to rust.
Years later, Hiro was rediscovered by Thomas, who had inadvertently gone down his siding after his brakes failed on a hill. Fearing that Hiro would be scrapped if he was found, Thomas vowed to restore Hiro to working order, with the help of the Steam Team. Using spare parts from the Steamworks, Hiro was patched up so that he could steam again and go to the Steamworks to be overhauled. Unfortunately, Hiro had to run away when Spencer was hunting him down, and without his injector, he began to break down again. Hiro was placed on another siding, where the other engines came to see him.
Eventually, Thomas decided to tell the Fat Controller about Hiro, who agreed to have him restored. Hiro was brought to the Steamworks, where Victor oversaw his overhaul. After he was restored, Hiro helped Spencer after he had an accident and worked to complete the construction of the Duke and Duchess' summerhouse. Despite all that the engines had done for him, Hiro became homesick, so the Fat Controller arranged for him to return to Japan. (TVS; Hero of the Rails)
Hiro was later brought back to Sodor to help the engines on the North Western Railway with the increasing workload over the summer period. His welcome party was nearly delayed when Thomas forgot to inform the other engines about it while he was searching for a present for him, but Hiro reassured Thomas that having his friends at the party was already a good enough present. (TVS; The Biggest Present of All)
During his visit to Sodor, Hiro was given the job of taking flowers to McColl Farm. While he was at Brendam Docks, Hiro told Thomas to take the bees through the woods, but Thomas ignored him and went through a large meadow instead. The bees left their hives and refused to go back in, so Thomas used Hiro's truck of flowers to lure them back. This failed, so Thomas admitted to Hiro what he had done and took his advice, safely delivering the bees and returning the flowers. Afterwards, he apologized to Hiro love love