Elnini

Elnini is the het ship between Eliwood and Ninian from the Fire Emblem fandom.

Canon
Eliwood is one of three main lords in the 7th Fire Emblem game. Ninian is a quiet and mysterious girl traveling with her younger brother; on first glance, the two appear to be a dancer and a bard traveling the world, but the story later reveals that the main villain Nergal has been chasing them for the past few years.

Eliwood first meets Ninian when he rescues her from bandits during Lyn's story, but the two do not properly interact until the main story following the first story arc. Ninian blames herself for the tragedies the group suffered, including the death of Eliwood's father, but Eliwood reassures her that none of it was her fault. Ninian officially joins the party, becoming a playable unit after this talk.

The two are clearly attracted to one another, with Eliwood going out of his way to look after her and Ninian slowly falling in love with him. However, Ninian is a dragon taking human form, and dragons are heavily feared on Elibe. Ninian keeps her secret, but feels guilty and unworthy of Eliwood's affections for doing so. If the player pursues their support chain, Eliwood tells Ninian he loves her even if she can't tell her secret, and at the end of the game they will marry,

Fanon
Ninian's only love interest option is Eliwood, so it's perceived as the game is pushing her as his love interest, added to the fact that Ninian have a crush on Eliwood outside their supports. She is arguably the most popular het ship for Eliwood since Fiora and Lyn have other romantic options that are perceived as more interesting by some fans. Due to the absence of Roy's mother in The Binding Blade, it was commonly assumed that Ninian died in childbirth due to both her fragile appearance and the canon detail that her life would be shortened if she stayed on Elibe. More rarely, others assumed she survived the birth, but died while Roy was still a toddler.

That said, Ninian herself was the subject of heavy controversy, some fans finding her problematic and antifeminst due to being dependent, quiet, and her role as a damsel in distress during the game before properly joining the player's army. This, added to the fact that if she marries Eliwood, despite the protests of her brother that is aware that her life will be short if she lives in the human world; points that  she needed willingly leave everything behind: her family, worried brother, life spam and possible friends only to marry and support a man. It should be noted, though, that Nils will give her his blessing should she reach A support with Eliwood, with Ninian torn between following her heart and staying beside her only living family.

The scene which Eliwood pierced and killed her with the sword when he saw her true dragon form only to her ressurect later also  raised considerable criticism to the ship. It was even once argued that the game "rewarded" her for her weaknesses and codepency, by focusing her with Eliwood, as opposed to action love interests that can defend themselves Lyn and Fiora.

There is strong friction with Elilyn and Elifiora shippers, largely due to the game system of multiple canon endings and arguments over which is 'most canon' or 'most deserving' of being canon. Some Eliwood x Ninian fans could get defensive of their OTP, or even militant in their insistence that the pairing is canon ignoring that Lyn and Fiora are also canon wives of Eliwood. Fans of the ship say the supports between Marcus and Lilina in FE6 strongly hint that Ninian is Roy's mother. due to her liking Illia flowers, the homeland of Ninian.

Trivia

 * If Ninian and Eliwood marry, Roy is 1/4 dragon.