Lucissa

Lucissa is the family ship between Lucina and Lissa from the Fire Emblem fandom.

Fire Emblem: Awakening
Lissa and Lucina are both are royals of the Ylissean Exalt bloodline, being aunt and niece respectively. Despite being related to each other, they share no supports. Lissa is the younger sister to Chrom, the current Exalt King of Ylisse and leader of a volunteer justice force called "The Shepherds", to which she also belongs to. Lucina is Chrom's daughter from a ruined future where the Fell Dragon Grima conquered the world, inspiring her to travel into the past to prevent Grima's forthcoming by any means necessary.

When traveling to the past, Lucina disguises herself as Marth, the Hero-King legend from a millennium ago. "Marth" ends up saving Lissa's life when she's being attacked, and Lissa ends up remarking that "Marth" is "dreamy".

Fire Emblem Warriors
Lissa and Lucina share a support together this time, where the two are panicking over a bug entering their tent. The support is, at best, simply a reference to Lucina's sibling support in Awakening, where she and her sibling similarly panic over a bug.

Fanon
Lucissa as a pairing is a rare one. They aren't paired together often in artwork or even in canon, to where even if they appear together, they most likely won't even refer to each other, or have much to say.

A romantic pairing of this ship may stem from the part where Lissa calls "Marth" dreamy. A common appeal of the ship is Lissa finding "Marth" attractive in the first place, then imagining how Lissa reacts to Lucina both being a woman and her niece. Such a line is never repeated after Lucina reveals herself as Chrom's future daughter, but the one-off line still managed to bring in a small amount of writings and images of the incestuous pair.

Fandom
FAN-FICTION

Trivia

 * In Lucina's appearances in the Super Smash Brothers series, she has an alternate color that bares Lissa's color palette.
 * Despite being younger than Lissa, Lucina is next in line to rule Ylisse. This is due to the fact that Lissa does not bare the Brand of the Exalt, a mark of Ylissean royalty that causes Lissa personal grief to be missing. Lucina has the Brand in her left eye, which is partly why she disguises herself as Marth.
 * To add on to this, despite Lucina being from the future, Lissa is technically younger than her.
 * Lissa finds "Marth" attractive before knowing that he is actually her niece from the future. This falls under the trope of Surprise Incest, and is even listed as a Video Game example of the trope.