Hiro is an adventurous youth and the main protagonist in Lunar: Eternal Blue and Lunar: Childhood's End. He lives with his grandfather Gwyn and his best friend Ruby. Hiro aspires to be an archeologist and is fascinated by stories of the valor of DragonmasterAlex and other heroes of old. However, unbeknownst to him, his destiny is about to change forever and it all begins with a journey into the Blue Spire.
Little is known about Hiro's earliest years and his parents are never specifically referenced in the series. He was raised solely by his adoptive grandfather Gwyn who inspired his love of history and archaeology.
Hiro is very adventurous and often goes exploring in the old ruins close by his home, though his grandfather isn't thrilled with the boy's recklessness. He heard many stories of heroes and their deeds and adventures in the past and he longs to adventure out into the world on his own someday. He has a very strong sense of justice and will help anyone who needs it. It is this quality that leads him to help a girl named Lucia, who desperately seeks the Goddess Althena and thrusts him and Ruby into the adventure of a lifetime.
When Hiro goes into the Blue Spire and first sees Lucia, he is struck speechless by her beauty and can't help falling in love with her (much to Ruby's dismay). He offers to help her in her quest to find Althena and she accepts. His kindness and dedication to Lucia is evident throughout the story and they develop a very strong friendship. However, when Lucia's feelings for Hiro cause her to question the consequences of her mission, she pushes him away in an attempt to steel her own resolve. When Lucia sees that Hiro is willing to risk his life and his world for her sake, she finally realizes that love and the power of the heart can overcome anything and allows her love for Hiro to show. However, she is forced to return to the Blue Star to fulfill her original duty, leaving Hiro behind. In the epilogue, Hiro searches for a way to travel to the Blue Star. He finally does and finds Lucia sleeping in her Crystal inside of the Crystal Castle seen at the beginning of the game. He wakes her up and as they go outside the sun is shining again on the Blue Star and some grass is growing as well, indicating that the revival of the Blue Star was beginning (most likely triggered by the prescence of Hiro or the defeat of Zophar). Lucia sheds tears of happiness and they kiss at the end of the game.
After the defeat of Zophar and Lucia's return to the Blue Star, Hiro wanders Lunar looking for a way to travel to the Blue Star to be with Lucia. As he journeys he meets a girl named Alice and rescues her from ghosts of Xenobia and Ghaleon who attempt to kidnap her. Though Alice is initially hesitant to interact with Hiro because his clothes are dirty and he seldom bathes, she warms up to him upon realizing that Hiro is a genuinely good and caring person. Hiro tells her that his girlfriend is very far away and that he is looking for a way to get to her.
Jean and Ronfar meet Hiro and Alice in a passing caravan and protect her while she is sleeping at night when Ghaleon's ghost comes for her again. Jean tries to convince Alice to join them on the caravan but she refuses. She is shocked when Hiro stays with her and swears to protect her.
When Xenobia and Ghaleon strike again, Leo returns with the Dragonship Destiny and Hiro summons the Four Dragons to stop them. After Alice is able to overcome her Vile Tribe blood and banish the ghosts of Xenobia and Ghaleon, she asks Hiro where his girlfriend is. He points to the Blue Star.
Alice laments to herself that she does not deserve the first man she fell in love with (Hiro), but wishes that he will find a way to Lucia on the Blue Star.