I'm gonna level with you guys for a sec here: I don't really have plans for any more posts about the au after this one, so if you guys want me to elaborate on something you can go ahead and ask. Other than that, this is the last planned post.
• Do I even have to say it?
• Avatar of the Mother of Puppets. In case it somehow wasn't clear to anybody here.
• The appearing completely naked the first time she and Sherlock meet is both for the bit AND a power move on her part showing herself completly, knowing full well that as an avatar of the Eye he cannot see her because she is an avatar of the Spider.
• Obviously has things to hide, but a girl can have some fun on her free time.
• Has spies on the royal family and knows about all the late gossip because the Rot isn't the only fear that likes crawling into things and her job gives... easy access.
• Sherlock becomes frustrated with the Eye as a result of not being able to find Irene after receiving the phone.
• As a side note, John "Marked by the Slaughter" Watson does not find Sherlock throwing the american dude off the window incredibly attractive, no siree. Totally straight dude over here. Don't know what you are on about.
• This happening right after his conversation with Irene about the both of them totally not having a thing for Sherlock regardless of their sexualities.
• She still tricks Sherlock into giving up Mycroft's defense plan. He still finds out she is in love with him without her knowing. The Eye sees through her because that is not part of the Spider's plan. Both of their eyes glow in that moment.
• Mycroft is pissed. Irene's demands here puts his possition as the head of the Institute in danger and that is part of his big plan.
• When Sherlock responds to her "I was just playing the game" with "I know. And this is just losing" stung a lot more and in so many more ways as an avatar of the Spider.
• My poor sweet dear Molly.
• Has begun the Avatar of the Lonely experience by the time John appears, but this only makes the process faster. Also favored by the End, she does work at the morgue.
• Watching Sherlock be so openly Obsessed with John exacerbates her loneliness to a point that it takes some time for people to actually notice her in a room. This is not voluntary at first.
• Similar to John, does not really know what's going on untill it's too late.
• We're skipping over exactly what goes on in the short period of time Molly is with "Jim" but needless to say she's a lot closed to the Lonely by the end of it.
• The Reichenbach Falls is an extremely last resort plan in this au mainly due to the fact that Sherlock knows it will most likely tip a lot of his friends over to the fears.
• When he comes back the damage control is far greater than in the series. I'd say not only is John close to becoming an avatar when he comes back, so is Molly (the both of them fully in the know of what's going on at this point, save for maybe the intentions and concrete involvement of the Holmes Siblings).
• Little tangent here but the Reichenbach Falls fiasco is also what finally gets Lestrade targeted and marked by one of the fears. Mycroft just so happens to be the reason he doesn't die during that incident (not the Reichenbach Falls but a different police operation).
• Since Johnny decides to get as physically far away from the Institute as possible (again, very Melanie of him), Molly does a bit of a Martin and takes over Sherlock's responsibilities as the Archivist with totally not traumatic at all results.
• Actually does the f*cking archival job. Mycroft, as head of the institute is kind of happy that someone is finally doing it, heaven knows the archives are an absolute mess after years of being exposed to Sherlock; but he is also a bit confused and concerned because nobody is supposed to be doing it.
• This is how all of them actually find out what in hell's name is going on with The Fears. During the timeskip. Molly connects the damn dots and tells both Greg and John about it.
• Greg continues his existential crisis and John does not want a part in aaaany of it.
• When Sherlock comes back and finds out about all of this he has a talk with Mycroft and then proceeds to do damage control for all his friends one by one.
• Manages to push Molly away from the Lonely to a decent degree. Has to plead for it because holy shit my dude you treated this woman so poorly.
• If we went into an extinction storyline after season 3 she would most likely play a big part in it due to her relationship with Moriarty.
• The single reason John is still somewhat sane by the time Sherlock comes back. We do not hate on Mary Watson in this house.
• When we meet her she's as reformed as can be as an avatar of the Slaughter (she was an assassin after all) and is in possession of a camera with a broken lense (iykyk).
• John is of course not aware of any of this.
• Sherlock though, immediately knows there's something absolutely wrong but can't really tell what it is.
• At first he thinks it might be another avatar of the Spider, which is why he is a lot more wary of her than in the series.
• After Sherlock comes back, things kind of fall back into routine once both Mary and Sherlock decide the other is not too harmful to John and that both of them are working towards the same thing, having John not become an avatar.
• John know Sherlock approves of Mary because he is not actively giving her psychological trauma.
• No, John still doesn't know what's going on with Mary and Sherlock is not telling. Cause he doesn't know either. He does explain some things about himself to John though.
• Mary knows John is marked. John doesn't know Mary knows he is marked.
• All is well until Magnussen threatens Mary.
• Sherlock breathes a sigh of relief when he finds out exactly what Mary is. Aaaand then proceeds to get shot.
• Pulls a Jon Sims in a coma and, after decades of avoiding it, becomes an avatar of the Eye.
• What follows goes the same as in the series. Sherlock lures Mary, John finds out.
• After going back to the flat Mary confesses that she was a former avatar of the Slaughter and Sherlock correctly deduces that she was most likely part of an special intelligence unit formed by the government with people marked by the fears.
• She happens to already be working for Mycroft so no need for an institute contract. She is already, technically, part of the staff.
• John wants to commit atrocities against him more than on average after that one in particular.
• In all fairness, Mycroft also wants to commit atrocities against John and Mary.
• Here Mary also tells them about the camera, which Magnussen is after, according to her.
• The Christmas Party still happens in the Holmes family home. John makes the same choice here as well aaaaaaand then proceeds to go along with Sherlock's unhinged plan and fucks shit up.
• Not only do they get Mycroft's laptop to Magnussen, they also bring the camera.
• He breaks it. He breaks the camera.
• Magnussen is defeated. This is a polite way of saying he gets brutally murdered. Again.
• Mary lives (for now) cause season 4 does not happen nor exists.
Special Note: Mrs. Hudson is just human. Not marked. She just has been adopted by all the marked + avatars in town, apparently.