Imprinting

"It's not like love at first sight, really. It's more like... gravity moves.... suddenly. It's not the earth holding you here anymore, she does.... You become whatever she needs you to be, whether that's a protector, or a lover, or a friend."

- Jacob Black explaining to Bella Swan about imprinting.

Imprinting is the involuntary mechanism by which Quileute shape-shifters find their soul-mates.

Description
When a shape-shifter imprints on a specific person, he becomes unconditionally bound to her for the rest of his life. When it happens, the experience is described as being gravitationally pulled toward that person while a glowing heat fills him; the connections of everything else become severed, or simply secondary, and only the imprintee is left to matter, leaving the shape-shifter with a deep need to do anything to please and protect the person.

Imprinting occurs only after a wolf's first phasing. It can happen with anyone, regardless of previous personal feelings. It happens the first time he sees the human object of his imprinting; if the shape-shifter does not react to a human subject the first time he sees them after he phases, that means he will never imprint on that human.

Imprinting can't be forced on anyone, no matter how much the shape-shifter may want it, as shown by Jacob Black when he tried numerous times to either imprint on Bella Swan or get over her. The same goes also for Leah Clearwater, who didn't go looking around the way Jacob did, but admitted to either wanting to imprint or be imprinted on. How imprinting will be for her is currently unknown because she is the first female wolf in their tribe's history.

It is unknown whether the shape-shifter could go one day without being in contact with his imprintee, the separation involved potentially causing both of them pain. What would happen if a wolf is rejected by his imprintee is also unknown, though this is assumed to be almost impossible; the imprinter is deemed to be the "perfect match" to the imprintee; he will be anything she may want or need, making rejection extremely unlikely. Should it happen, however, the imprinter may feel unspeakable pain, but he will still respect her decision. He also won't be able to find another person who can satiate his loneliness or replace his soulmate.

It is implied that once a shape-shifter imprints he will be able spend the rest of his life aging alongside his imprintee once he is able to quit phasing. It is also implied that should the imprintee be long-living or immortal, the imprinter will live alongside her as long as he can phase every so often. It is unknown whether shape-shifters need to stop phasing and for how long before breeding.

Stages of imprinting
There are stages to imprinting, especially if the shape-shifter imprints on a child, or otherwise the imprintee is very young.

If the person is young, the shape-shifter will act as an older sibling.
 * First stage

As the person grows older, the shape-shifter will also come to be their best friend. They become intimate friends. Meaning, their feelings for each other are changing into romantic feelings. (Remember, this stage may or may not happen to the imprintee, but the imprinter will fall in love with his imprint. They will not 'see' any other woman or man in a romantic way, at all. Their imprintee is all he/she cares about and he/she will love her/him even if those feelings aren't returned.) When the imprintee is old enough, the shape-shifter's feelings grow into romantic/sexual love.
 * Second stage
 * Third stage
 * Fourth stage

The shape-shifter will be at all times very protective and loving to the imprintee.

Rationale for imprinting
The reason for imprinting is unknown. Sam Uley believes that a shape-shifter imprints on the person with whom he has the best chance to reproduce. How this applies to Jacob Black and Renesmee is debatable. Billy Black, however, thinks that imprinting is designed to make the shape-shifter stronger. While never stated directly, Billy's theory may explain Jacob's imprinting on Renesmee; she may provide him with greater support, or if they can reproduce, some vampiric traits (such as hardened skin, perfect memory, or supernatural gifts) may be transferred to shape-shifters, reducing their weaknesses in human form.

Shape-shifters known to have imprinted

 * Sam Uley on Emily Young
 * Jared Cameron on Kim
 * Quil Ateara V on Claire Young
 * Paul Lahote on Rachel Black
 * Jacob Black on Renesmee Cullen

Imprintee
Thus far, only male shape-shifters have imprinted, invariably on a woman, and regardless of her age; while Sam Uley, Paul Lahote and Jared Cameron have imprinted on young adult or adolescent women, Quil Ateara V and Jacob Black have imprinted on young children.

Unlike her imprinter, the imprintee can choose whether she'll accept him as her 'soulmate' or not. It is however implied that a rejection is highly unlikely, since it is said that it would be very hard to resist the levels of "commitment, compatibility and adoration". It has also been noted that the imprintee feels incomplete without the wolf nearby.

But if she does choose someone else over the shape-shifter, he will be in deep emotional pain, though he will still respect her choice.

After-effects of imprinting
Even though the shape-shifter has imprinted, it doesn't necessarily mean he won't suffer a little if it can't be helped, though he would instantly break the heart of his loved one before this imprinting. In Sam Uley's case, he felt horrible on Leah's heartbreak after imprinting on her cousin Emily, giving him reason to hate the vampires for his phasing. The shape-shifter has to be very careful around his imprintee, as anger could cause him to phase, and, if too near, he could accidentally kill or scar her for life.

If the imprintee is too young to date, and may understand when she gets old enough, the imprinter would still not date, since he does not 'see' any other face to do so. It is unknown what effects the imprintee's rejection would have on the imprinter, but it is implied that he would enter an irrational rampage and hurt her by accident.

In addition to imprinting, the shape-shifters' sense of duty toward the pack and the tribe is probably the only other important element in their lives, leading to some hardships in their lives, among which having to balance their duty toward pack and tribe against time spent with the imprintee, and their aging on two different tempos due to the shifter phasing while the imprintee does not.

If something horribly drastic were to happen so that the imprintee sacrifices herself for her family/tribe, then the same consequences of the third wife's sacrifice are bound to occur, bringing much pain to all involved.

Apparently, even after the shape-shifter has stopped phasing and lived a so-called 'normal' life with his soulmate, he could still phase back into a wolf if he's angry enough, most notably, if his imprintee has come to any harm.

Pack laws
"If you kill her, you kill me."

- Jacob to Sam and his pack

If an imprintee is killed, the imprinter will never be able to forget or forgive the person responsible for her death. In the case of the killer being another pack member, whether purposedly or by accident, the inevitable result is a fight to the death. To avoid feuding bloodshed within the pack, the La Push shape-shifters established their most strictly followed custom, by which no wolf may kill a fellow wolf's imprinted one, with no exception recorded.