Taken from the megatokyo forums:
Yandere? A Japanese term for a person who is initially very loving, caring, and gentle to someone (or at least innocent) they really, truly like and care for a lot before their romantic devotion becomes mentally destructive in nature, often through violence and/or brutality. The term is derived from the words yanderu (病んでる?) meaning a mental or emotional illness, and deredere (でれでれ?) meaning to show affection. Yandere characters are mentally unstable, and sometimes are incredibly deranged and are not mentally sane, often using extreme violence and/or brutality as an outlet for their emotions.
The Yandere survival guide:
When obsession wins over love and you’ve got yourself an immensely affectionate stalker instead of a girlfriend, you have a yandere on your hands. These are the kind of girls that break into your house while you’re away, hide under your bed while you’re at home, schlick directly under you while you sleep, come out when you’re gone again, schlick again in your bed while licking and humping your pillows, and then proceed to check your messages to see if you’re involved with another girl. They usually don’t have any kind of higher ideal or ethical policy; they sometimes don’t even view themselves as people so much as an entity made out of the impulse or desire to be with their man. A yandere is awesome because it’s outwardly impossible to tell that the girl is completely insane; she has just enough presence of mind left over to maintain a convincing facade, and God help everyone around her if she decides to drop it. If you don’t react well, things could get messy, so in the off chance you don’t want to enjoy the fruits of your yandere’s darker exploits, here are several things you need to take into account.
Remember your objectives:
-Her mental integrity should be kept at a reasonable level and maintained.
-She should still love you unconditionally.
2. Be sure to remind her how much you love her and basically compliment her as you would any women. Be careful about criticism, though, because she’ll probably go a little over the top in attempting to fix this problem, and if she can’t, she’ll try to fix your perceptions of this problem instead. When prompted, re-affirm your hatred of those other skanky, dirty whores. Putting down other people is fun anyway, right?
3. When she starts talking nonsense, she is being put under stress. This stress is based on the belief that you are being unfaithful or planning on leaving her. Pacify her with constant, unadulterated attention and sex. Remember that one of the best things about yandere is that they’re completely devoted to you, so why shouldn’t you return at least some of the favor? This entire fiasco can be summed up in a single line: It’ll be great if he was nice and looked only at me. Yes, only at me. He can’t look at any other girls. I’ll look only at him, so he should look only at me. It’ll only fair, right?
4. Contact with the opposite sex in public should be kept to a bare minimum — the assumption should be that she IS watching. When she’s with you and you talk to other women, she’ll either flaunt you in front of them or discourage prolonged conversation. In either situation you should play along, expressing your undying love for your yandere all the way. In the latter one you should cut off contact as soon as she gives a prompt to do so. Occasionally she’ll become openly hostile to women she finds you speaking with, so diffuse that bomb before it explodes. Female relatives may or may not be accepted by the yandere, though for the sake of her facade she’ll usually ignore them.
5. The yandere likes to do things for you, so keep her busy doing chores that make her feel she is strengthening the relationship. This is one of the best parts about the yandere since she’ll spoon feed you if you ask her to and she won’t even see it as strange.
Now that you’ve won the affections of one of these very, very insane women, you surely want to know how this benefits you, right?
LOYAL: She will never — NEVER — betray you. Even when you’re dead.
LOVING: She knows the meaning of true love like no other girl, or even you, will ever know. Some of the love is for your own good.
CARING: She takes her entire budget of caring and places it all on you. Other people are… irrelevant.
PROTECTIVE: No bad fortune, villain, or evil conniving cheap slut will be allowed to have their ways with you for long.
HATRED: For other girls as pure as the darkness between the stars.
DETERMINED: She will never — NEVER — give up. Even if you end up hating her for it. She’ll never let you down, either.
OBSESSIVE: There is pretty much no limit to how far she’ll go just to get your attention. Once you go yandere, you can’t go back.
BRUTAL: Why should she go easy on those who threaten to steal you away from her?
PROACTIVE: Friends? Family? Better get rid of them before they start taking up precious time you could be spending with her.
DETESTING: Everyone that isn’t you.
Besides a very, very affectionate partner, there are plenty of ways to have fun using her unique features. For example, pick some girl you know likes you, give her your phone number and ask her to call you. Put yourself in a position in which you are with your yandere and open to being approached by this girl. Then confide in your yandere how this girl won’t leave you alone. Count the days until this girl disappears or stops communicating with you entirely. If the yandere decides to kill her rival right in front of you, marry her as soon as rationally possible.
One of the few potential cons that I can see is that intellectual conversations are nearly impossible with your yandere. She can’t comprehend anything outside of the context of your relationship with her. War in Iraq? You are saying you think she’s too clingy and so therefore some cheap slut is poisoning your mind against her. The nature of the universe? You are trying to break up with her so therefore some cheap slut is poisoning your mind against her. It’s okay to participate in activities that don’t involve her, by all means, please do, but it’s very, very difficult to get your yandere involved in anything that doesn’t directly have to do with her loving you. It’s not impossible, but I prefer to keep mine in the kitchen baking or knitting and would rather not provoke her.
Speaking of my own personal methods for dealing with yandere that might not work for some people, when a girl I’ll accept becomes yandere for me, I become yandere for her. That’s right, all that crazy shit. No looking at other men, not allowed to leave my presence for more than 3 hours, etc. I’ll stalk my precious yandere all the time and make sure no other men can get near her. Well, at least at first.
The problem with continuing this practice is that you can’t out yan the yandere. It would only drive her to a higher state of mental instability. Think about it – you’re stalking her everyday. She realizes it’s YOU who’s the third person walking by her to the grocer’s, or getting her car fixed, or chatting with the neighbors as people jog by. She starts wondering, “does he think me unfaithful? But… but that’s impossible. It’s just him I care for – only him!”
Then the attempts to reassure herself begin. More painful, scarring sex play, just to let you know “this body is only for you.” No matter how violent or messy, she does it with a broken smile. The meals become dull as she starts going out less and ordering in more. Minor things she can pick up from faceless stores to show you that she doesn’t NEED other people, so long as she has you. The artwork of herself she leaves in your desk at work (should you bother to show, as you’re so busy being full of her and dumping bodies of the ones who’d dare even glance…). The jagged crying night sessions – tears spilling down her face as she smiles delightfully, her voice full of laughter as she takes on any abuse, just for you.
The moment of broken screaming when she realizes despite all this devotion, you STILL don’t trust her.
And then you walk in one day and find that she’s jammed the biggest kitchen knife she could find into her sexual organs. That tearful, joy-filled face saying, you know, darling, you were right, my thoughts were impure and clouded by other faces, so I punished myself, but now it’s fine. I’ve punished those involved, too, those evil people that caught me in my moment of weakness・
The police will be over in the evening to arrest you both on the collection of bodies in the basement unless you had already prepared an escape route for different but similar reasons. So yeah, you need a cut-off point for being yandere to your yandere.
DOUBLE YANDERE LOVE IS THE TRUEST LOVE.
Ahem. Excuse me.
Point is, give them too much love and they’ll begin feeling unworthy of you; it won’t matter how many times you reassure them that they’re perfect, they’ll constantly feel not up to your love. Eventually they’ll take for granted that you’re betraying them because every other woman is better than them, and shit will degenerate rather quickly. Still, if you treat them badly they will still consider that a gesture of affection, so it’s the same shit. Getting them pregnant may possibly be the correct answer. They’ll focus their attention on your love’s “fruit” and that will wash away many of their insecurities as long as you spend enough time with both them and your child. You’d have to make sure she’s not seeing your son as you though, or things may get really hot, if you know what I mean.
Ah, yes, the question of children, a problem with no easy answer. In general, yandere would make poor mothers, and the child would be at constant risk of being targeted by the yandere’s psychotic episodes. The yandere may very well reject the child and see it as competition. It’s not impossible, however, with enough care from her man. Some yandere object to the idea of children because they see themselves as beings which must not bear new life, but other yandere may be quite open to it, or even feel they would want it as irrefutable proof of your love. Regardless, they will bow to the wishes of their loved one, so it’s something that would take some struggling at first, but will probably work out in the end.
Some extra thoughts regarding the psyche of the yandere:
1. Yandere are not opposed to safe sex, but they are opposed to mechanical means of birth control. It’s not because they enjoy sex physically more than any other girl, it’s because they view sex more as a spiritual ritual in which they become closest to combining with their loved one; she will always demand sex to be as raw as possible. If birth control is desired, they will generally have no problem taking the pill and consider condoms to be a barrier to achieving oneness with you.
2. A yandere will never, ever share you, nor will she accept any kind of rival; to her, other girls are nothing but enemies. Yandere don’t feel the kind of isolation some normal girls might, and so will never believe themselves to be different or special to other girls. To a yandere, other girls have the same filthy desires and conniving thoughts as she does, which is why she loathes other girls so much; she firmly believes other girls are out to steal her loved one. If two yandere met over the same guy, they would launch a war that wouldn’t end until one of them was dead. No mercy, no surrender.
3. The yandere will almost never rape her loved one if they are still outside of a relationship. The yandere will attempt to attract you using conventional means, as the yandere believes from her own upbringing and education that this is the correct method for getting her man. If she knew she could get you by raping you at gun-point, she would do so immediately.
4. I think that sometimes the attraction to yandere is based on the childish, idealized belief that your love can cure her. PFFT. This is DANGEROUSLY NAIVE. “Cure” her? Why would you want that? Her being an obsessive, potentially-dangerous psychotic is the whole POINT. To say someone finds such a person attractive out of some misguided belief they can “fix” them is like saying a “chubby chaser” finds big women attractive out of some belief that he can get them in shape, when really he just really likes the fatties. In all likelihood the stress of a relationship would make her psychosis even worse. Yandere are crazy and there’s no way to make them feel at ease, and if you think you can then you’ll end up with either you or her dead, possibly both.
5. Yandere only ever overstep their boundaries if you’re overstepping yours, maintaining a facade of perfection elegantly – and scarily – up until the point where it must be dropped, and even then, they are often very forgiving, even often coming with warning signs if you look for them. If she’s becoming a nuisance, think of something to occupy her; remember, she likes doing things that will strengthen her relationship with you, so basically all you need to do is give her chores. This is pretty damned simple. Anyone with half a brain can get someone else to do everything for them. This is one of the yandere greatest pros: -20 in sanity in exchange for +20 in homemaking.
6. There is no guaranteed method to stop a yandere, but the most reliable action is certain, definite death, and even that is not infallible even when it has initially succeeded. Do not expect any obstacle, whether it be public authorities, the distance between nations, or what have you, to be able to hold back or contain a yandere: she has all the tools and skills she needs to get to you, and she will focus all that is herself into achieving her goals in relation to you – pretty much the only goals she has. Yandere are resourceful, and the only way she’ll die in any manageable fashion is if she submits to death by your hand or is caught completely off guard. The only way she can be caught off guard is if she doesn’t suspect your betrayal at all and thus hasn’t planned ahead so that in such a situation she can entrap you and force you (or your corpse) into a position where she has the (sexual) advantage, so keep in mind that she may have a trap set for you or otherwise some sort of auxiliary plan.