Water Mom

Lapiven is the non-binary ship between Steven Universe and Lapis Lazuli from the Steven Universe fandom.

Canon
Steven is the first person to free Lapis from her 1000 year prison inside the mirror. Because of this and that he earned her trust after the fight, he is the only person Lapis truly trusts to repair the psychological damage she has endured over the course of the original five-season series and during Steven Universe Future. She has a minor part to play in the Spinel movie but is otherwise not important to the plot.

After her painful fusion with Malachite, where she was imprisoned for months holding Jasper under the sea, she has a love/hate relationship with water. This is further inflamed when she meets the two new Lapises in Steven Universe Future. She sings a song for them "Why So Blue" and they all end up fighting, with Steven usually taking a defensive position and Lapis taking the offensive. At the end of this fight, the two Lapises are so impressed by Lapis Prime's power they agree to join Little Homeworld.

Following this, Steven breaks up with Connie and is en route to having a meltdown just like Pink Diamond did in the past, effectively repeating his mother's mistakes and putting everyone else in danger and causing a great deal of trouble.

Fanon
Fanon of this ship is often considered toxic at large by Steven Universe fans, or even pedophiliac—equating Lapis to something like a child groomer for any possible shiptease or real relationship between them. Care should be taken by fanfiction writers and fanartists to avoid this kind of contentious link, or such presumptuous arguments completely disregarded.

Such arguments have happened in the Steven Universe fandom before, such as Zuke's shipping of Amedot, the suicide attempt of a fanartist, PurpleKecleon's variant cover for Issue #8 of the Steven Universe comic and more.

Fanon usually holds Steven to be the superior over Lapis and he is commonly depicted emotionally manipulating her or forcing her be by his side or be abandoned. On the flip side, Lapis is usually seen with an enormous victim complex and unable to move on or let go of Steven.

People consider it an adult/minor ship and are uncomfortable with it on average, and even aged-up pairings still get some amount of flack, regrettably. This ship is comparable to other Gem ships such as Stevidot, Ameven, and Stevnel.

Fandom
FAN FICTION