Hamato Yoshi (2003 TV series)

Hamato Yoshi was an orphan, living in the streets of Japan with his best friend, Yukio Mashimi, in the 1960s. When Yoshi returned a 5-yen coin dropped by the Ancient One, he took them in for their honesty, raised them as his sons, and taught them Ninjutsu. They both fell in love with Tang Shen, another orphan taken in by the Ancient One. Shen loved Yoshi more. During this time, Shen found a rat in the house and kept him as a pet.

One night, Yoshi, Shen, and Mashimi saw a lone man being attacked by four ninjas. Yoshi and Mashimi decided to help the man and fought off the ninjas. The man was actually the Utrom Mortu and the ninjas were members of the Foot Clan. Impressed by their skill and already having his secret revealed due to battle damage, Martu offered to make the two Guardians. They accepted, despite their master's objections.

As a Guardian, Yoshi seemed to advance continually, while Mashimi never seemed to get anywhere. In anger, he murdered Tang Shen and betrayed the Utroms to The Shredder. Yoshi and the Utroms managed to escape with their lives. When Yoshi returned to the Ancient One, he found his master cradling Tang Shen's body. In anger, despite counsel from his master, Yoshi stormed the Foot's citadel and killed Mashimi in single combat.

With their Tokyo base discovered, the Utrom set up a new base in New York under the name T.C.R.I.. Yoshi went with them, taking Shen's rat with him. He named the rat Splinter to remind him of the splinters of anger and hate that drove him to kill Mashimi.

However, the Shredder followed Yoshi and tried to force him to reveal the location of the Utroms. Yoshi resisted and was killed. Splinter escaped to the sewers, where he mutated along with the Turtles. He proceed to teach them Ninjutsu, just as he had learned from Yoshi.

Yoshi was also a champion of the Battle Nexus.

Ninja Tribunal
It's revealed in The Lost Episodes that Yoshi and the Utroms tried to get the Ninja Tribunal's help in the fight against the Utrom Shredder, warning them that the alien may channel the evil one. Due to their refusal to help, Splinter partially blames them for Yoshi's death.

In episode, "Fathers & Sons", Splinter had procured Yoshi's ashes after his passing and made great strides to bring himself and the then-young Turtles to Japan. Yoshi's ashes were then laid to rest next to Tang Shen.

When the Tengu Shredder goes to attack Splinter, Hamato Yoshi manifested from the Turtles' medallions. He snatches the Shredder's trident and then slashes him with it, causing precious energy to leak from his armor. When the Tengu Shredder was on the verge of defeat, Yoshi manifests himself through the Turtles' medallions again, which shatters them and then he slayed the demon by slicing him in half.