Artemis was the princess of Archanea during the first war with Dolhr. Like Nyna, she was the last surviving member of her royal family. Before leaving Archanea, she handed over the Fire Emblem to Cartas and placed a curse on it to ensure Cartas would win the war. She then hid away at Altea, where she met Anri. To protect her from Dolhr, Anri left in search of the Falchion sword and eventually slew Medeus, bringing an end to the war.
Afterwards, Artemis married Cartas; though she and Anri loved one another, they knew that the nobles of Archanea would not accept Anri, who was a commoner, to become their king. People later referred to Anri and Artemis's sadness as being caused by the curse that she placed on the Fire Emblem, which became known as Artemis's Curse.
The curse seems to be inherited whenever the Fire Emblem changes hands in order to save Archanea, as is indicated by the star-crossed love between Nyna and Camus in Fire Emblem: Shadow Dragon and the Blade of Light. Though the two loved each other, they ultimately have to be separated due to Camus's allegiance to the King of Grust, the enemy. In the end, Nyna has no choice but to wed Prince Hardin to preserve the Archanean bloodline. Even if Camus were to have joined Marth's army, Camus still would have probably been prevented from marrying Nyna as he was not a noble, just like Anri at the time.
Artemis was the Greek goddess of hunting, often rendered as a female archer.