Yandere is one of the most recognizable anime character types, following after tsundere and deredere. Yandere characters appear sweet and conscientious, but they give in to aggression easily, especially when it comes to their crush.
Girl yanderes tend to blush all the time and are easily flustered. They can switch from a moony shrinking violet to a jealous rage-beast in the blink of an eye, which tends to be used for comic relief in many anime. The reigning character trait of a yandere is their propensity for infatuation and obsessive love. Boy yanderes tend to be characterized as more manipulative. Their crushes are so intense that it could be argued that their kind of love isn't really even love.
10 Lucy & Kouta (Elfen Lied)
The Lucy personality aspect of Kaede in Eflen Lied is a pitiable character. She's born of immense trauma and abuse, and it greatly warps her sense of the world. She has sparse experience with the kindness of others.
Lucy attached herself to Kouta, who she's known since childhood, but her love is a twisted one built on obsession. Lucy is manipulative, violent, and compulsive, and though she and Kouta both have love for each other, she's not equipped for a relationship.
9 Kotonoha & Makoto (School Days)
At first, Kotonoha seems shy and quiet by default in School Days. It isn't until she starts to really care for someone new that her more obsessive and explosive side comes out.
Kotonoha acts toward Makoto like a jealous dragon guarding its hoard, and she won't hesitate to spit fire if she feels pushed aside or threatened when it comes to that relationship. Kotonoha slips into denial when Makoto expresses his feelings if they don't align with what she wants out of him.
8 Yona & Soo-Won (Yona Of The Dawn)
Soo-Won is clueless about romance, but he does show a sustained affection for Yona — until he tries to kill her in the first episode of Yona of the Dawn. Naive and lovestruck Yona is completely blindsided by his betrayal and still holds on to the hair ornament he gave her before he ruined her life and expelled her from her throne.
Thankfully, it's pretty obvious, even from the beginning, that Yona and Hak are the endgame romantic pairing. Soo-Won is a tortured, uncertain person, and he doesn't bring out a good side in Yona.
7 General Esdeath & Tatsumi (Akame Ga Kill!)
General Esdeath sets her sights on Tatsumi after she sees him smile in Akame Ga Kill!. She doesn't truly care for him based on who he is as a person. Rather, she covets him for what he symbolizes to her.
Esdeath is cold-blooded and violent at the best of times, but the strength of her infatuation with Tatsumi often only makes those tendencies worse. She spurns any possibility of a romance with anyone else without a second thought, all for her one-sided love for Tatsumi.
6 Sakura & Sasuke (Naruto)
So many Naruto fans don't like Sakura and Sasuke as a pairing, citing that a relationship built on fangirling is creepy and childish. Sakura gets extremely petulant about gaining Sasuke's attention and seems to fall for him without even knowing who he is.
Sakura's love for Sasuke and efforts to vie for his attention have left worthy friendships broken by the wayside. Sakura does grow up a bit more as the two age, but the foundation of her feelings for Sasuke are about as yandere as it gets.
5 Yukako & Koichi (JoJo's Bizarre Adventure)
Yukako is as beautiful as she is troubled in JoJo's Bizarre Adventure. "Bizarre" is in the name, after all, and her successful relationship with Koichi upholds the show's reputation.
Yukako and Koichi's relationship begins with a casual kidnapping, as Yukako's every thought is bent on having Koichi for her own. Yukako doesn't always lead with aggression, though. There are times when she's pretty demure. Those times don't last long, as she has some wicked mood swings. Eventually, Yukako gets better and gets into a relationship with Koichi.
4 Yuki & Zero (Vampire Knight)
Zero straddles the line between tsundere and yandere in Vampire Knight, and it results in a rather distasteful personality. He wants Yuki, but he also has no problem being incredibly rude to her. When others give her problems, Zero flies off the handle to defend her.
When Yuki starts to form a connection with Kaname, the worst side of Zero starts to come out. He gets jealous and belligerent about the two growing closer, even though he doesn't treat Yuki very well himself. His personality and values aren't all bad, but his relationship with Yuki is awful.
3 Friagne & His Doll (Shakugan-No-Shana)
In Shakugan-no-Shana, Friagne is head over heels in love with his doll, and it is incredibly creepy. His personality vacillates between calm contemplation and berserker rage. Though unstable, he's by no means naive or unintelligent as some yanderes can be.
Friagne weighs his actions and crafts detailed plans. Friagne's doll, Marianne, serves as his main character motivation. The sentient doll and the collector both love each other in a very yandere/yandere fashion. Marianne is utterly devoted to her master, and Friagne wants to find a body for her.
2 Ren & Akira Sohma (Fruits Basket)
Ren's chief personality traits in Fruits Basket are her obsessive tendencies, manipulation tactics, and her horrendous temper. She's only ever loved one person, Akira Sohma, who she worked for as a maid when they first met.
Ren saw through to Akira's deep sadness, and that is what initially endeared her to him. Ren is so desperate to maintain Akira's affections that when she discovers that they are having a daughter together, she insists on raising her as a male so there would be only one female whom Akira loves. She's one of the most reprehensible villains in Fruits Basket.
1 Kyouya & Erika (Wolf Girl And Black Prince)
Kyouya of Wolf Girl and Black Prince has an extreme yandere personality, and naive Erika pays the price for it. He is cruel to Erika and then extremely jealous of her attentions, describing her as "his."
Though Kyouya abuses her, Erika will also grow incensed, even aggressive, if someone insults Kyouya in front of her. Though Erika cares for Kyouya despite his rancid personality, thankfully, even she will get fed up with his awful behavior and give him the cold shoulder, but it's really not enough. Their relationship overall is incredibly manipulative, isolating, and dishonest.