Sigurd is the main character in Fire Emblem: Seisen no Keifu and one of the most famous characters in the series. The fourth game in the series, in fact, is considered by many fans one of the best for it's many improvements to the franchise, and Sigurd's popularity has consequentially grown, even if he is a playable character in only the first half of the title.
However, sales and game quality aside, Sigurd's strong valor and sense of justice, his emotional and passionate story and his tragic death are the main causes of Sigurd's rise to stardom from the other Fire Emblem lords.
In 2006, when Masahiro Sakurai created a poll to help determine which characters would be featured in Super Smash Bros. Brawl, Sigurd was included, although he placed below a fellow Fire Emblem character: Ike.
Born in the kingdom of Grandbell, Sigurd is a direct descendant of the legendary swordsman Baldo, from whom he inherits his sword: the Tyrfing. His lineage forced him to initiate training as a knight at a very young age. It was during this training that he met his friends Cuan of Lenster and Eltosian of Nodion. One night, they made a pact to each other, saying that they would always assist each others' dukedoms in times of desperate need. Cuan would later marry Sigurd's sister, Ethlin, strengthening their bond.
Once adult, Sigurd became Lord of Chalphy Castle and one of the most important leaders in the continent of Jugdral.
After the kidnapping of the cleric Adean, Sigurd leads an attack against the kingdom of Verdane, during which he meets his future wife, Diadora. Although local villagers tell him that she is cursed, he marries her anyway, as he does not believe in curses. He then leads an invasion and occupation of Agustria after his friend Eltosian is imprisoned by Chagall, King of Agustria. During this time his son Seliph is born.
After being framed for the assassination of Prince Cult, Sigurd is accused of treason against Grandbell and forced to take refuge in Silesia. He then manages to return, eliminating the lords that placed the blame on him, only to be killed by Alvis. Upon meeting him after killing the lords, Sigurd finds out that not only is Alvis a part of the conspiracy, but that he has also married his amnesiac wife, Diadora, to produce an heir to take Cult's place. Assassinated at a young age, Sigurd was beloved by his allies and all the people of Grandbell.
A number of years after his death, Sigurd is avenged by his son Seliph.