Net Revenants

Net Revenants are a malevolent and cunning subspecies of the undead, commonly counted among the most dangerous of the supernatural entities infesting the Internet. Surviving their attacks is extremely rare, with some larger Initiate groups estimating close to 95% mortality rate among the targetted Non-Initiates. Even Initiates are typically easy prey unless they happen to be particularly powerful and knowledgeable.
Thankfully, they are also extremely rare, due to a very specific set of circumstances required to spawn them. What's more, the length of their existence tends to be counted in minutes, and it's unheard of them to launch more than a single attack before ceasing to exist. However, this also means that they aren't a well-known threat, resulting in them often taking even veteran Initiates off-guard.

Birth

Net Revenants lack corporeal bodies, being best described as cunning, vengeful and sadistic ghosts inhabiting internet chatrooms - video or text ones. They are only born from established chatrooms whose members have committed suicide while blaming others for it. The chatrooms themselves do not have to be a consistent thing. For as long as a group of friends regularly made videoconferences on for example Skype, the first prerequisite will be fulfilled.
If the group in question continues their internet meetings after their member's demise, one of them will be interrupted by the Net Revenant's manifestation. This typically occurs on the anniversary of the suicide, the birthday of the victim and so on. The entire group has to be present, with no one unrelated present in their homes. The real problem is that it doesn't matter how much time has passed since the suicide - as a result, sometimes even experienced Initiates end up forgetting about the date.

Manifestation

Once manifested, Net Revenants will begin to attack their victims. Net Revenants possess instinctual knowledge about every secret of their victims that was, at some point, recorded by any electronic device connected to the internet. They will use those to turn their victims against each other, taunt and emotionally torture them. Until they either commit suicides or are murdered by the Net Revenant, for example for failing its current death game.
Every infected machine extends a zone of control (typically up to fifty meters) within which the Net Revenant can act as an incredibly powerful poltergeist. Attempting to leave before the Revenant's bloodlust is satisfied is not an option, a fact that is typically stated by it openly during the initial manifestation. Trying to flee will result in a particularly vicious and gruesome death in front of the camera (or immortalized with a photo displayed on the text chatroom). For intimidation.
Its kills tend to be personal and viciously sadistic. Net Revenants are legendarily vindictive and cruel.

Fight

Net Revenants are extremely powerful. Their lifespan is counted in minutes, as stated. Unlike normal incorporeal undead, they spend the entirety of their power during that short time. Engaging them in regular combat is a possibility, but generally considered a bad idea. Net Revenant has to be first drawn out of the Internet.
All infected machines have to be destroyed simultaneously through magical means. As one can expect, this is simply unachievable if there is even a single Non-Initiate within the infested network. If it does happen, it will fragment the Revenant, causing a split copy of it to be manifested from every computer or phone in the infected network as a noncorporeal ghost with powerful telekinetic ability.
If even a single copy survives, the remaining computers and phones will regenerate, and the manifestation will continue. It should be attempted as soon into the manifestation as possible - every killed victim means one less copy to deal with... making the remaining ones more powerful. If even a single machine wasn't destroyed at the same time, the rest will regenerate without forcing the Revenant to manifest. But it will make it angry.
If defeating the Net Revenant is impossible, there are still other means of survival. The first one is persuasion. Net Revenants are sentient beings. They only know what their human self did plus whatever they managed to glean from the internet. If their attack is misdirected (and you proved it), it might leave you alone. Achieving its forgiveness is also a possibility. Both options are extremely hard to achieve due to how incredibly furious and hateful they are. But not impossible.
The second survival option is pure luck - or extreme lack of it. Sometimes, the Revenant might get satisfied with its vengeance before it runs out of victims. Sometimes, it will instead decide to let you live - in a way that will make you wish you have died. Unless they are former Initiates, Net Revenants do not know how magic works. Some of their Fates Worse Than Death can be recovered from through appropriate spells.
The last option is outside help. Net Revenants are chained to their victims as much as they are to the computers. They cannot attack anyone else. A sapient entity that they aren't connected to will shatter their zone of control on entry. This will rescue that particular victim but might prompt the Revenant to lash out on whoever's left in its thrall. However, this is something that will happen by luck mostly. Net Revenant will counteract any attempts to call for help (though it can be achieved if someone is quick on their feet and resourceful).

Net Revenant

Summary

Type: Undead
Subtype: Incorporeal/Informatic
Status: Kill-on-Sight
Estimated Numbers: N/A
Censor's Veil: Temporarily Uncensored.

Alignment

Creator Power: N/A
Alignment Status: N/A
Sanity Damage: N/A
Corporeal Stability: N/A
Magic: N/A

Combat

Combat Behaviour: Ranged/Area Control
Threat Level: 5-6
Physical Damage: Invulnerable
Magical Damage: Vulnerable
Glyphs: Vulnerable
Notable Weaknesses: Described in Article