Is OTHER wrong in the post ? POST : Starting this with an explanation of the situation.

I was previously employed as a desk jockey in a company where the department was roughly twenty people of particular demographics and I was the sole member of a polar opposite demographic. I had worked there for about two years with half of my duties being transferred from another person who worked there with one foot out the door and a job title one significant step ahead of my own. I also had taken an extraordinarily nasty account which required at least intermediate familiarity in an uncommon dialect of a foreign language to cover correctly. I had basic familiarity which was more than the rest of the department combined.

My performance was considered somewhere between "good" and "great" through the first year, somewhat notable as I was being judged on a scale used for 5-10 year veterans. I wasn't some infallible rock star at the job, but I was definitely good enough to keep around and the only person to handle the bilingual account properly in years.

One person who had previously been employed at this company had come by to visit with a few people as she had recently left work at another company in town. She was interested in getting her previous position back, or at least something close to it. Her previous position was on par with the person whose duties I had taken over. My direct manager told her that nothing was available at the moment and she had already trimmed a few positions in the past few years.

As you can imagine, this led to a "That's a nice job you have there, I think my friend will take it" situation. I was assigned a new account, the previous owner refused to assist, I inevitably make an error treating the account similarly to my others, and I was let go on thin pretenses. While nothing was actually said, it seemed rather clear to me that I was the one to go as I did not fit the department demographic while the previous employee did. I had an easy time claiming unemployment, but I didn't have the documentation for any sort of legal action. In the end I just wanted to be done with it.

The AITA part is that I proceeded to anonymously report my former manager to corporate HQ for drug abuse. The company was excessively harsh on any potential drug use. I happened to overhear the day before my termination that my manager had obtained a few prescription pain pills from a friend after spraining her ankle rather than take half a day off for a doctor's visit, thanks to the fact that said manager had two voices, loud and super loud. I don't particularly care about that kind of thing and saw the company drug policy as being absolutely Draconian, but I also wanted revenge. She thought she was safe as we had been through our "random" drug testing only a few weeks prior. Due to violating drug policy, she was terminated immediately with cause.

There are also a few complicating factors.

According to her social media, previous manager had swiftly risen in the ranks in another company before a sudden "departure" and taken a new job at the previously mentioned corporation at a much lower position at what was likely a quarter of previous pay, although she had risen to something not far from her first position by the time I worked for her. After she had joined the second company, she had a child who happened to be special needs and very expensive to care for, pushing her to become a bit of a workaholic.

Previous manager also made a few vague, plausibly deniable comments to me regarding some physical attributes of mine being desirable. I acted oblivious and nothing came of it, although she did continue the comments on occasion.

TL;DR version- Former manager terminated my job to give it to a former co-worker/friend of hers, I got her fired for her minor transgressions, this may have seriously screwed up her life and family life, but she also was a creep. Was I in the wrong?