Marth

Marth is the main protagonist of Fire Emblem: Shadow Dragon and the Blade of Light and its sequel, Fire Emblem: Mystery of the Emblem. He is the prince of Altea and the wielder of the legendary Falchion. He also appears throughout the Super Smash Bros. series as a playable fighter in every title since Super Smash Bros. Melee, which is also his first time appearing in a game outside of Japan.

Super Smash Bros. Melee
In Super Smash Bros. Melee, Marth is an unlockable character. His design in this title is based upon the one used in Fire Emblem: Mystery of the Emblem. While Marth was a heavily requested character in Japan, he and his series were unknown to Western audiences before Super Smash Bros. Melee. Marth can be unlocked by playing as every default character in a Melee match, clearing or failing Classic with all of the default characters, or by playing 400 Melee matches, and then defeating Marth when he challenges the player.

Marth is a fast character with average power and below-average weight. However, all of his attacks are stronger when hitting opponents closer to the tip of his sword. His standard special is Shield Breaker, a slash that can be charged to be more powerful that can also instantly break an opponent's shield when charged fully. His side special is Dancing Blade, a series of sword slashes that can be altered depending on the direction inputted on the control stick. His up special is Dolphin Slash, an upward slash that has Marth leaping into the air. Finally, his down special is Counter, in which Marth delivers a counterattack when hit.

In an interview, Masahiro Sakurai reveals that he had struggles including Marth and Roy in versions of Super Smash Bros. Melee outside of Japan. He pushed hard for Marth's inclusion as he deemed him to be a "fun" character to use. Marth's voice clips are Japanese in all versions of the game, reflecting the series' Japan-only status at the time. Marth is voiced by Hikaru Midorikawa, reprising his role from the Japanese release of the Fire Emblem: Mystery of the Emblem OVA.

Super Smash Bros. Brawl
Marth also appears in Super Smash Bros. Brawl, alongside fellow Fire Emblem character Ike. He is unlocked by either playing 10 Brawl matches, clearing Classic Mode on any difficulty, or by meeting him in Adventure Mode: The Subspace Emissary. For the first two methods, he will be fought afterwards, and must be defeated to be unlocked. Marth's stage entrance involves him entering the stage via warp magic.

Although Marth's moveset is unchanged, his Shield Breaker has been changed to a move in which he thrusts his sword. Marth was given a Final Smash, Critical Hit, a powerful strike that deals heavy knockback to whomever it hits. In addition, the sweetspot on his sword has been made smaller, and his grab has a shorter range.

Adventure Mode: The Subspace Emissary
In Adventure Mode: The Subspace Emissary, Marth is first seen standing over a castle, looking down at the desert, where he sees a Subspace Bomb exploding in the distance and creating a large hole in space that remains in the middle of the desert. Marth takes out his sword and runs over to it to inspect it, while defeating some Primids along the way. As he finally approaches the Subspace Bomb-made hole, Meta Knight comes out of the sky and attacks Marth, thinking that he is an enemy. The two fight, until they are abruptly beset by a horde of Primids.

The swordsmen begin cutting Primids in half, swiftly realizing that they are fighting for the same causing, and eventually end up back-to-back as they continue to fight off the Primid horde. As they eventually charge and begin beating back the swarm of Primids, Ike happens upon the scene and manages to stop the Ancient Minister from dropping another Subspace Bomb. The trio of warriors then pursue him until he manages to get away.

Later, Marth and the others discover a strange tank in the middle of The Wilds. After a bit of hesitation, Marth follows the others towards the tank, which then reveals itself to be Galleom. After Galleom's initial defeat, it tries to get away, but ends up falling into The Ruined Hall. It eventually emerges carrying Lucas and the Pokémon Trainer into the sky while the Subspace Bomb in its body counts down to detonation. Lucas manages to free himself and the Pokémon Trainer from Galleom's grasp, and they are rescued from their fall by Meta Knight, tagging along with Marth's team for the duration.

Marth and his companions eventually arrive at the foot of the Glacial Peak, where they find Meta Knight's ship, the Halberd, attacking the Great Fox. Meta Knight leaves Marth's team to scale the mountain in an attempt to board the Halberd. After a while, the Ice Climbers fall to where Marth and his team are, and are faced with more Primids until the group of Mario, Link, Yoshi, Kirby, and Pit intervene.

Eventually, every character comes together to track down the evil's source in Subspace, discovering that Tabuu is the entity behind the Subspace Army. Everyone, including Marth, gets hit by Tabuu's Off Waves and turned into trophies. However, King Dedede had foreseen this happening, and created timed badges that revive whoever was wearing them. Reviving himself along with Luigi and Ness using the badges, King Dedede heads off with his companions to rescue a majority of the others, Marth included, before settling the score with Tabuu.

Super Smash Bros. for Nintendo 3DS / Wii U
Marth is also a playable fighter in Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U. He is one of the several unlockable characters from Super Smash Bros. Brawl who was made a starting character for these games, with the others being Luigi, Toon Link, Lucario, Sonic, and Captain Falcon. Super Smash Bros. for Wii U includes a few more: Ness, Ganondorf, and Jigglypuff. Marth's appearance has been updated, incorporating elements from Fire Emblem: Shadow Dragon and later games. Some aspects of Marth's moveset have been buffed and nerfed, though aside from this, his moveset is unchanged from the previous game, though most of his sword swinging attacks now feature a trail that glows brighter at the end to make the sweetspot more visible. Another Fire Emblem character, Lucina, shares a similar moveset with Marth.

Super Smash Bros. Ultimate
Marth returns as an unlockable playable character in Super Smash Bros. Ultimate. Unlike his previous Super Smash Bros. appearances, and for the first time in the series, Marth is fully voiced in English. Yuri Lowenthal voiced Marth in the Nintendo 3DS game Code Name: S.T.E.A.M. and a few of the dubbed Fire Emblem games that followed and reprises his role in Ultimate, providing newly recorded voice clips for the overseas release. His voice actor in the previous games, Hikaru Midorikawa, continues voicing Marth exclusively in the Japanese version of the game, with his voice clips also re-recorded, rather than reusing his voice clips from the previous games. Marth benefits from universal changes: he sports faster mobility, his short hop timing is reduced, his aerials have less landing lag, he can use directional air dodges once again, and he can use any ground attack out of a run and any aerial attack on a ladder.

On a side note, as with several other returning fighters, Marth's (as well as Roy and Ike's) victory theme has been sped up compared to the previous installments.

In the World of Light, Marth is seen when the fighters opposes Galeem for the first time. He is the one of fighters who can be unlocked earlier within the mode, alongside Mario, Villager and Sheik. A puppet fighter of Marth, alongside one of Meta Knight, is shown battling Link during Hero's reveal trailer. Aside from World of Light, Marth can alternatively be unlocked by clearing Classic Mode twice as Yoshi or Lucario or by playing 1 hour of VS matches while having at least six characters unlocked.

Classic Mode route
Marth's Classic Mode route involves him fighting reptilian opponents, representing his final quest to slay an Earth Dragon in Shadow Dragon and the Blade of Light.

Snake's codec

 * Mei Ling: Snake, have you heard the saying "Politics makes strange bedfellows"?
 * Snake: Don't tell me that's a Chinese proverb.
 * Mei Ling: Err, no... It means that when the going gets tough, you might need unexpected partnerships in order to succeed. Marth was a prince whose kingdom was usurped. He didn't even have an army to fight with him. But as he battled his way forward, he found new allies to fight at his side, and in the end, he was able to reunite the war-torn land of Altea.
 * Snake: So he built his army from the ranks of his defeated enemies...
 * Mei Ling: Marth did his share of fighting, too. Even when he had an army, he was always alongside his men in the thick of battle. Then he was betrayed by one of his most trusted friends. I can't even imagine how that feels...
 * Snake: I can.

Palutena's Guidance

 * Pit: Get a load of Mr. Fancy Pants here.
 * Viridi: Is that jealousy I detect in your voice, Pit?
 * Pit: Why would I be jealous of Marth?
 * Viridi: Well, he's a prince, for starters. A handsome prince. And you're just—
 * Palutena: Anyway, Prince Marth's most dangerous attack comes from the tip of his sword. Avoid his blade when you're at midrange.
 * Pit: So I should either attack him from a distance, or get up close and personal.
 * Palutena: He's got a counter as well, so be on guard when you go hand to hand. If you're attacking from afar, use items to improve your chances.

amiibo

 * The first hero from the Fire Emblem series, Marth is the prince of Altea and descendant of the hero Anri. He’s known as an exceptional swordfighter, swinging his blade with grace. He and a small group of stalwarts fought to free Altea after it was invaded by the kingdom of Doluna and the dark dragon, Medeus.

Super Smash Blog bio
"Marth is an exceptional swordfighter with a long reach. He'll do the most damage with attacks using the tip of his sword, so spacing is an important factor."

English

 * "Keep your eyes open!"
 * "This is it!"
 * "I won't lose!"
 * "The day is mine!"
 * "I live to fight again!"
 * "I cannot afford to lose!"
 * "My turn!"
 * "Predictable!"
 * "Nice try!"
 * "We'll each need to take down about ten." (Adventure Mode: World of Light)

Trivia

 * In an interview, Masahiro Sakurai stated that he wanted to add Marth into the first Super Smash Bros. as a playable character, but was unable to do so due to time constraints. When asked why he considered Marth, Sakurai said that he wanted a character who was similar to Link in the style of a swordsman.
 * Marth is the only character in Super Smash Bros. Brawl whose back is turned at the camera when facing right and whose front faces the camera when facing left. All other characters do the opposite.
 * This is perhaps in reference to how the player characters are oriented in the first eight Fire Emblem games, with the players on the right side of the screen facing left during the normal fight scenes.