Stalkers

Stalkers are a relatively rare type of sentient undead born from an obsession. One that managed to transcend the death itself. While not a powerful type of undead, they tend to be disturbing and (often) extremely cunning. What makes them really dangerous is the fact that death in their case tends to be temporary - and they are very motivated.
What's probably the worst, their minds remain unchanged during the process, allowing them to freely exploit the human society and culture to achieve their goals.

Basic Information

Anatomy

Stalkers have three basic states. They can switch between them depending on the circumstances. Each of them looks notably different and has to be treated differently if faced.
The masked state makes them look like they used to look before they died. They are visually and audibly indistinguishable, for both Initiates and Non-Initiates. Worst of all, they can walk through standard warding glyphs when masked, although it does cause them discomfort. This can be noticed unless the Stalker is good with acting. Thankfully, this state can only be maintained temporarily, although this is greatly dependent on how satiated the stalker is.
The unmasked state is the default state of the stalker, best described to be their former human state but entirely colourless. Stalkers entire body (not clothes, however) is of pure white colour, producing a deeply unnatural look. In this state, they are kept at bay by the warding glyphs. However, sufficiently cunning (and sated) stalker can keep their true face hidden for long.
The enraged state occurs when the Stalker is either attention-starved or driven into temporary madness by something (for example, jealousy). Stalker retains its pure white look, but its strength is greatly enhanced. Depending on how deeply the stalker has 'lost it', it can also start looking less and less human. The list of possibilities includes impossible changes to facial features up to complete lack of those, too wide limbs, electronic distortion and apparent darkening of everything around them (while keeping themselves as visible as they used to be).
They are generally treated as revenants in this state, recognizable only by their pure white colour.

Genetics and Reproduction

Stalkers are undead and thus effectively barren. The new ones are born only when a human being dies with an obsessive desire to be with someone. Mundane stalkers, people who committed suicide due to unrequited love, a bit too zealous groupies and so on. If the body isn't disposed of properly and quickly, there is a high chance that they will return as Stalkers.
Some degree of pre-death face-to-face contact is required for a Stalker to be born. For example, not every groupie who dies will turn into a Stalker - but if her idol slept with her (and then left her the next morning), she might devolve into this. At least if she then killed herself or died while obsessing over him. Emotions overflowing while death comes is a necessity for the Stalker to be born.

Dietary Needs and Habits

Stalkers thrive off the attention of their 'victims'. For as long as they interact with each other, the Stalker's hunger is sated. The more emotionally charged the interaction, the better. This can also heal their injuries and even resurrect the Stalker. For example, if something slays your stalker without you there to witness, but you expected to see the stalker tomorrow, it'll be enough to make it come back to 'life' and show up.
Their feeding isn't directly harmful to the people they are bonded to. They are cases of Stalkers and their 'victims' managing to co-exist in relative peace and harmony, in fact it's not unheard of for nastier and more ambitious Initiates to manipulate someone into becoming their stalkers. A properly satiated and 'trained' stalker is basically a perfect bodyguard, ready to take a bullet (or a fate worse than death) in your stead without a second of hesitation. Discovering that you were manipulated, however, often drives stalkers homicidal, sometimes to the point of them transforming into revenants.
Their common weakness in every state is their 'victim'. If they die, stalkers die alongside them. They can also banish the stalker by rejecting their existence wholeheartedly - if stalker is then slain, they'll perish permanently. However, even the slightest longing, subconscious one even, might be enough for the stalker to persevere and return to their unlife, even years later.
Co-existence is rare, however. Their nature is that of an obsession, and while it can be de-escalated without unmaking the Stalker, it'll never go away entirely. What's more, a Stalker has only limited control over itself in an enraged state and can go berserk for example due to their bonded individual meeting another woman/man once or twice too much. Even to this there are exceptions, however.

Additional Information

Perception and Sensory Capabilities

Stalkers possess a standard, human set of senses. The only difference is their natural ability to know where their bonded human is. Distance doesn't matter, stalker will know where you are even if you are in the Earth's orbit, or another universe entirely. They will also roughly understand your current state (emotional and physical).

Stalker

Summary

Type: Undead
Subtype: Corporeal/Sapient
Status: Kill-on-Sight [With Exceptions]
Estimated Numbers: Unknown
Censor's Veil: Displayed as humans.

Alignment

Creator Power: N/A
Alignment Status: Varied
Sanity Damage: Immune
Corporeal Stability: Immune
Magic: Can use only in masked state.

Combat

Combat Behaviour: Impersonator/Berserker
Threat Rating: 1 [2 in Enraged State]
Physical Damage: Vulnerable
Magical Damage: Vulnerable
Glyphs:Vulnerable
Notable Vulnerabilities: None