(The above video becomes relevant when I start discussing D. I couldn’t insert the video exactly in the position I want, sorry!)

In this ‘mini’ theory, I explore this concept posted by Marlene:

From this, I take that A and D are two different people. Call it a mini A Team, so to speak.

Let’s start with the A.

The A in AD is for Mona. It just has to be her - let me tell you why. She was original A. She wants her game back. The girls still treat Mona like shit despite her apologising time and time again AND despite both going through the dollhouse together where the girls clearly saw that Mona is was not the enemy! Hanna literally gave Mona the silent treatment when Mona came to her bridal shower party with a smile and a loving present. Hanna then threw the thoughtful, personalised gift in the trash, causing Mona to say “it seems everything I do ends up this way”. Spencer exclaimed “what is she doing here!?” in 620 at the Lost Woods Resort. It is precisely this type of constant rejection that brings back that anger from seasons 1 and 2 when she was A, and now she wants to do it all over again. She wants to punish the liars for constantly rejecting her. One way she did this, was by taking Hanna from them.

She scared the girls, whilst simultaneously getting Hanna all back to herself. Besides, wasn’t that Mona’s original motive for being A? That she lost Hanna to the girls? (It was Alison’s death that reunited the girls, not Mona’s texts, so there is no plot hole here in Mona’s motive.)

Obviously, Mona never killed Hanna despite kidnapping her. It was just a doll that she hung from the bell tower! The symbolism in this is that she kidnapped her out of hatred, but didn’t want to overly harm her because a love remains.

Then how do we explain this horrible stuff, if Mona simultaneously loves Hanna?

Let me quote Mona; the one who did this to Hanna: “it’s much easier to forgive an enemy than it is to forgive a friend”. So yes, Mona is extremely angry with Hanna! But do not forget the symbolism here: Mona would have never killed Hanna. This is all just a game. Emotional venting. That’s all it’s ever been. Well, with Mona, at least. Wait until I explain the D in AD!

Let’s not forget that Mona was supposed to be watching Noel in 710, yet somehow he escaped. Also, amongst the ever so minor plot progression in 6B we did learn that Mona called CeCe from the Two Crows Diner the night she was killed. Clearly, Mona was involved in the sequence of events the night a Drake family member was killed. Mona followed Spencer and Toby in 620 to the discovery of Mary’s Radley file! This bitch is really involving herself in the Drake-related-stuff yet it’s going unnoticed! (I highlight Mona’s constant involvement in the Drake family because this provides evidence to her teamwork with D in AD - D’s main aim is associated with the Drakes.) Also, we can’t forget the “thanks for giving me Hanna” text. That was entirely A, not D, if that makes sense.

Mona involving herself in the Drake family issues is exact proof that Mona is the A in AD; helping their partner, D, which I will explain now.

Unfortunately I can’t include it here at this point in the post, but please go to the above video posted by the official PLL Instagram. It gives us confirmation that Spencer indeed was AD’s target that night. It was no accident that Spencer got shot, it was entirely deliberate. Jenna missed, and so AD swooped in to finish the job.

The D in AD must stand for Drake. 

Noticed how everyone in the Drake family has been killed?

- Spencer was shot (99.9% chance she’ll survive, but it’s the attempt to kill that is significant)

- Jessica, who was born as a Drake (but has the last name DiLaurentis because she married Ken) was killed. Surely, this is the reason why they have not told us who killed Jessica yet - why are they dragging it on for so long if the answer is as simple as her evil twin killed her!? Well, maybe Mary didn’t kill Jessica. It was AD.

- Charlotte was most likely killed by AD, following this trend of all Drake family-members being killed. Therefore, AD is playing a game - AD is not avenging Charlotte’s death because AD is the killer!

- I won’t be surprised if something bad happens to Mary soon. She’s a Drake. Surely, again following this trend, Mary is on the hit-list too. It is entirely possible that the reason she was even in the house in 710 is because she had been kidnapped by AD! It kind of looked like she was in a dark room, perhaps a closet… maybe she wasn’t intentionally there to help Jenna or AD like we thought. Maybe AD kidnapped Mary and it was AD’s plan to wipe out the Drake family that night (with the help of Jenna).

The big question remains: why does AD hate the Drakes? Well, going back to what I stated before, I believe the D in AD stands for Drake. Maybe the A in AD stands for their first name, or it could be for their partner’s name - that is, A and D are two different people. Nonetheless, I believe AD is a Drake, and something terrible happened to them (similarly to Charlotte’s upbringing) and they’re here to kill their entire family. And that’s why this is the most ‘deadly’ A so far - they’re literally here to kill family. How brutal.

- It’s worth noting that as per THIS THEORY, I am 100% sold that Bethany is also a Drake. Mary had two daughters: Spencer and Bethany. (I should add to that theory, that the Doctor that Aria and Spencer visited in 7A said “I dealt with one of Mary’s babies”, whereby the ambiguity implies more than one baby.)
Who killed Bethany? 610 revealed that was Mona (then Melissa buried her). So, following this trend of Drake children being killed… who started it? MONA, when she killed Bethany! 

- Note that the last time we saw Eddie Lamb, he was delivering to Ezra some drawings that Bethany had done! It’s no coincidence that Eddie Lamb went missing once he involved himself in the Drake family. (Again, there’s more evidence that Bethany is indeed another one of Mary’s daughters!)

What do you all think about this idea of A and D being two different people who are working together? They have different agendas, but of course, we have seen them at times cross paths. 

(Crossed paths? When? Well, for example, AD knew that Hanna had ordered Mona to watch Noel in 710, so what does AD do? Call their partner and say “release him”, that way AD can shoot Spencer easier because there’s another person in the house to stop Spencer from escaping.)