Generally speaking, when a yandere falls in love with someone, they tend to play for keeps. No matter how much blood has to be shed, no matter how much suffering they inflict your common-or-garden yandere will do anything for and to be with the one they love.
So what would happen if two yanderes got together?
In theory this would seem like an ideal set-up. With two individuals sharing such an unquestionably insane devotion to one another, you immediately bypass the typical shenanigans that accompany the archetype. Right?
Uhhhh, that's where things get interesting...
When left on their own, these couples will at worst be Sickening Sweethearts. But try to get between them however... watch out because come hell or high water they do whatever to takes to remain together and chances are things will not end well for you and whoever gets it their way.
And if this pair comes with a side of Outlaw Couple, Serial Killer, Ax-Crazy or anything else less-than-legal, expect that little Berserk Button to become several magnitudes more difficult to avoid. If such a couple is also married, this can also overlap with Unholy Matrimony.
See also Psychotic Love Triangle, if another Yandere is butting-in with the couple.
Anime & Manga
- This is the premise of Love Death. Shouko and Akkii are two high schoolers whose love for each other drives them to try and kill each other Once per Episode.
- Christine: Despite the latter being a sentient 1958 Plymouth Fury, the relationship between Arnie and the titular Christine slowly develops into this.
- Natural Born Killers: A big part of what has come to make Mickey and Mallorey Knoxx so appealing to the media and the public is their psychotic devotion to one another.
- Suicide Squad (2016): Unlike how their relationship is depicted in the comics, Harley Quinn and the Joker are portrayed here as being utterly devoted to one another. Though by Birds of Prey, it's turned sour enough for Harley to dump him.
- Zits: A downplayed and Played for Laughs example. While Rich and Amy don't demonstrate the psychosis traditionally associated with yanderes, the other characters find themselves alternatively bemused or disturbed the the obsessive level of devotion they show one another.
- You: Season 2 is one long deconstruction. The climax reveals that behind Love's "perfect girl" exterior, she is a cunning, remorseless murderer who killed Forty's au pair for molesting him, and she murdered Delilah and Candace for threatening to expose Joe, when Joe himself couldn't. However, when she does this - and reveals she knew all along that Joe killed Beck, and planted herself to find him - Joe is repulsed by her, and only doesn't kill her because she's pregnant with their baby. They stay together, but Joe is miserable and loathes her.
- Stalker x Stalker by Merryweathery features the main yanderes Junko and Yukio madly in love with each other. While fairly harmless when nobody gets between them, when somebody does get between them... well, it ends the way you expect.