Sethrika

 is the het ship between Seth and Eirika from the Fire Emblem fandom.

Canon
Seth is a knight of the kingdom of Renais, while Eirika is the princess and twin of Prince Ephriam. Seth canonically has feelings for Eirika, though he can end up marrying the cleric Natasha if the player so chooses.

On the night that Castle Renais fell, King Fado ordered Seth to flee with Eirika. Together, they escape. Their support conversations focus on this event. In their A-Support, Eirika tells Seth that she felt something more that night, but Seth puts his duty before his feelings, and tells her they cannot be together. However, he admits that he felt those same feelings.

If their A-Support is achieved, the ending confirms they marry with the blessing of Ephriam.

Fanon
Many fanfiction focus on the pining aspect of their relationship, and how duty gets in the way of love. A parallel can be drawn between Seth and Carlyle of Jehanna. Carlyle was in love with the queen of Jehanna, but put his feelings aside and loyally served his country instead. However, this love ultimately led to him betraying Jehanna and killing the one he loved. Most fanfiction authors see Seth as the antithesis of this, handling his feelings in a better way.

On AO3, it is the third most written ship in the Fire Emblem: The Sacred Stones tag.

Fandom
AO3

Fanlore