Whew! So here goes nothing. I have been with my stepkids' father for about 3 years. About a year ago, we all moved together in the same home, along with my 9 year old son (at the time.) DH (I guess that means dear husband), has physical custody of his kids, SD12, SS14. Not legally but physically. Mom is on 2nd/3rd relationship within that same amount of time, now with women. Often financially/housing unstable so now he has the kids. When I first began dating DH, I noticed the the SD, who was 9/10 at the time, was incredibly clingy to new people she met, including me. Like after a week or so of meeting, climbing in the bed with me while I'm watching tv and cuddling. She has also done this to her adult brother's GF, who she had just met. This was alarming to me and I told her father, who didn't seem as alarmed to me as I would have expected. I also learned very early on that SD is a liar. When I said something about it being an issue, her parents minimized it, saying "yeah, she tells stories." Before we lived together, I noticed odd things she would do. For example if someone was outside very briefly, she would lock the door so the person would have to knock to come back in. She would say she didn't do it, which was untrue. I noticed that she had this facination with candle wax. I purchased them wax warmers for their home before I moved in. DH thought the "was was exploding" because he would come home daily to wax spilled all over the table, floor, splashed on the wall. If he had candles lit, there would be wax around the table by the candle and finger holes in it. He believed absurd/freakish things were happening instead of the obvious. When she came my home, I noticed wax splattered the same way. I didn't give her a chance to lie, I just told her I know she is doing it and to stop. She continued for the nex couple of years until I banned her from having candles once we lived together. I then began to notice she had an interest in fire. I would find lighters in her room, burned pieces of paper, burn mark on her bed, all which she "didn't know how any of that happened." I have asked her several times, not to eat in her room because she was leaving cups, plates, ect. Instead of stopping, it increased SIGNIFICANTLY. She would sneak plates of food in her room and lie about it. For example, she could be cooking something in the microwave. 1 minute later, she is gone, the food is no at the kitchen table or the trash and she is in her room. I'd ask her if she has the plate of food in her room and she would tell me no with no hesitation or blinking. But my BS would actually SEE HER and tell me she's lying. I would check her room and she has dirty plates, cups, empty food containers, empty boxes of cereal, spoons. DOZENS of candy wrappers, chips bags under her bed, hidden in bookbags, in her closet, in drawers, under her pillow, EVERYWHERE. If I am missing something and I ask her if she has it, not only will she say no but also "I don't even know what that is. I've never seen that in my life." You look under her bed or a drawer and she has it hidden there. I have literally dozens of perfumes and told her that she could use any of them EXCEPT 2 specific ones that were discontinued favorites. Out of the dozens of perfumes, guess which ones are missing?  THE SPECIFIC ONES I ASKED HER NOT TO USE. I knew she had them but she would say no, ever so innocently. I would tell her father that she has it and he would say, well IDK what you want me to do because she said she doesn't. I actually smelled it on her one day and got fed up. I looked in her bookbag, and of course there they were . . .basically empty. I ask her to stay out of my room while I am at work.   I return to see lights on in the room that I didn't leave, glass jewelry box cracked, missing costume jewelry, missing money, etc. Again, she swears she has not been in my room or taken anything. Well how do you explain your pajamas on the floor in my room? No explanation. I have always purchased my BS nice clothing, quality sheets, new shoes often, etc. I started to do the same for the SK but the brand new clothes would go unworn, thrown in bottom of the closet. Would keep the same nasty sheets on the bed until I demanded that they change them as if they refuse to use the nice linen.  I had a class pet in a tight lid shoebox on the porch. She went outside to "check on it" and offered to tell me "the pet is fine!" I didn't ask. 20 minutes later I went outside to check the pet and it was gone. Of couse, she didn't do anything. When I check her on stuff , she will squint her eyes and stare at me without responding. . .when her dad isn't home. When he comes home she is super fake, asking me the same script everytime even if it makes no sense. Ex, "how was work today?" knowing it is a holiday and no one worked. "How did you sleep?" in front of her dad, when she literally saw me hours ago. I could be in the kitched cooking or cleaning and she has come into the kitchen and simply JUST STARED AT ME. This is just the tip of the iceburg yall. EVERYTHING OUT OF HER MOUTH IS A LIE. Even things that seem pointless. Once I was confronting her about something and she said she wanted to go live with her unstable mother, who does NOTHING for them but make empty promises while she acts like a childless 21 year old. When I told her father she said that, of course she said she did not. Don't lie ON me to my husband. She's visiting her mother for this summer and we are checking her room. It is HORRIBLE. Her room looks like it is in an entirely different house. I've have already disengaged because it has felt like I am the only adult that sees that she has a problem. I was told I'm targeting her, yet she walks around with the bullseye. She has had FOUR phones within a year and has broken them all. 3 of them she was asked how they cracked so badly and she says she doesn't know. I refused to add another phone on my plan, but DH feels like she needs it for safety. The last one she had for a month, and now that one too is broken. DH has gotten better with seeing that there is some type of issue with her as of recently. I think the behavior is only going to get worse. If she returns to my home after visiting her mother, I am positive the behaviors will increase significantly. We are moving soon and I have communicated with DH that she cannot live where I am, in a nutshell. I think her lies and manipulation are dangerous, her lying about playing with fire is dangerous, her hoarding brings pests and rodents, and she is just overall sneaky and a bad influence on BS and SS. Honestly I think she depises me for pulling back the curtain like the Wizard of OZ. How dare I call her out and shine the spotlight on her when for years she was the "Pretty Princess who liked to tell stories." On top of that, I don't think she likes the fact that her father is happy with me and divorced, even though her mother left the marriage to be with women. This is already long enough, but I needed to get this off of my chest. Mind you, we have only lived together FOR ONE YEAR!