Marth is a character from Tokyo Mirage Sessions ♯FE.
Marth is the central protagonist of the original game, Fire Emblem: Ankoku Ryū to Hikari no Tsurugi and Fire Emblem: Mystery of the Emblem. Prince of Altea, he is forced into exile when the nation Dolhr invades following the death of his father Cornelius, who was killed due to the betrayal of King Jiol of Gra in favor of Dolhr and the pontifex Gharnef. In the conquest of Altea, Gharnef also claimed the sacred sword Falchion and took Marth's older sister Elice hostage.
After spending several years in the nation of Talys, Marth matures into a young man. With his remaining Altean allies and the backing of Talys, he sets out on a quest to liberate Altea, rescue Elice, recover the Falchion, and put a stop to Dolhr and its ruler, Medeus. During his journey, he meets Princess Nyna of the kingdom of Archanea and is gifted a magic shield known as the Fire Emblem.
Following the defeat of Gharnef and Medeus, Marth lives a peaceful life in Altea for several years until trouble begins to brew when Hardin, the new emperor of Archanea and Marth's ally in the previous war, orders Marth to put down a rebellion in the nation of Grust. When Marth falls into disfavor with the corrupt Hardin and Altea is conquered by an Archanean alliance, Marth journies to recover magic gems required for the Fire Emblem to regain its full power.
Eventually, Marth acquires all but the last gem, which happens to be in Hardin's possession. Marth manages to defeat Hardin and recover the gem, but in doing so also learns that Hardin had not been acting as himself; he had been possessed by Gharnef, who survived his defeat in the previous war. Marth returns to Dolhr, where Gharnef plots to resurrect Medeus, and defeats them both for the final time.
For his deeds, Marth is entrusted with the rule of all the nations on the continent of Archanea and goes down in history as the Hero-King.
Tokyo Mirage Sessions ♯FE
Marth is an important aspect to the main storyline of the final chapter. Although Marth doesn't appear physically, he helped out by reviving Itsuki, giving him strength and becoming one with him temporarily for the final battle against the evil dragon, Medeus.