Ephika

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

Fire Emblem: Sacred Stones
Ephraim and Eirika are the twin prince and princess of Renais. They were both gifted the Sun Brace and Moon Brace respectively, the items which allow them to gain access to the Renais Sacred Stone they are fated to protect as the royals of Renais. Later, they are gifted the twin weapons of Siegfried the Lance and Sieglinde the Sword respectively.

They both have a series of supports which can result in a paired ending. Their supports reinforce the care and love they have for one another as brother and sister. They also reveal tokens of affection that they have for another, such as Eirika's childhood habit of stroking Ephraim's face. They end on the note of vowing to always stay with one another.

Their resulting paired ending has them rebuild Renais together with Ephraim as King.

Fire Emblem Heroes
This information recalls from the mobile game Fire Emblem Heroes and as such as a semi-canon to non-canon nature with the mainline games.

In a map that introduces players to Sacred Stones characters, Ephraim comments on people misinterpreting his and Eirika's relationship. Implying that they are not incestuous, howeveer Eirika has lfavour text which refers to the Japanese myth of twins being reincarnated lovers.

Additionally, they share a Duo Unit together as children.

Fanon
Ephika is a controversial ship due to the incestuous nature of it.

Fandom
The Ephika tag on Ao3.

Trivia

 * The signature weapons Siegfrid and Sieglinde which Ephraim and Eirika use respectively refer to Norse mythology; in Richard Wagner's interpretation, these of these myths, the twin characters are incestuous.
 * Eirika claims that Ephraim taught her to use a sword yet he is a lance unit, implying that her use of stabbing swords, such as rapiers, is due to his influence.