A ghost can become a poltergeist if the right circumstances arise

part 4

Days passed, weeks even, and memories slowly came. But none more involving Levi.

"Oh! There was this one time when I was a child when I was nearly run over by a cart! Jeez that hurt, I can almost feel it now."

"I remember meeting Mike for the first time, he sniffed me, but then stopped. I suppose it is because I smelt of lab chemicals, not a very good thing to breath in if you have an acute nose."

"The day that Moblit was assigned as my assistant! That was a fun one! He nearly had a heart attack whenever I did anything, tried to drag me out of my lab at least 4 times a day, 3 to eat and one to sleep, eventually gave up and fell back to once every day or two."

"Umph!" and here she finished chewing, "The day I joined the scouting legion! It was raining, but I didn't care, I got to join and meet all of my new squad members! Sorta like with my first day of training, I got shouted at but it was rather fun in a way!"

"Hmm, that was when I discovered my urge to study titans instead of just hunting them. I had decided to kick one of the severed heads and had found it much lighter than possible. Previously I had been fueled by rage, consumed by it, I wanted to take out every last titan in existence or die trying. Now though, because of that I study these titans and attempt to learn more about them. I figure people say that I am weird or traitorous for my interest in titans but really this is a valuable project isn't it?"

No matter what though, no more memories of her time spent with Levi surfaced. It seemed that the only memory that made her head hurt was that one involving him too. If he could punch through walls he was pretty sure he would. Give him some titans and he would slaughter all of them to cool off. Funny thing about being dead, it gave Levi more time and ways to express emotions, he didn't have to live up to and become a title anymore, he was just Levi.

The day of the planned wedding came, but she didn't notice. She didn't wash her hair like she had promised.

"Come on shitty glasses, you told me that you would wash your hair today, it is our wedding day after all. I said if you did I would arrange a mission to capture some titans for you. You owe me a wedding, and that debt was supposed to be paid today, with clean hair." This frustrated Levi to no end, and it hurt a bit. He had been hoping that maybe, just for once, something would slip in and she would remember to wash her hair, if for no reason other than just because she wanted to that day, on the surface at least. She had promised, she always kept her promises, always, so why did she have to break this one? He wandered off to another part of headquarters to see, just briefly, how others were faring, but if he had stayed he would have seen her shower, and for seemingly no reason other than boredom and wanting to, she had washed her hair nice and thoroughly. When he came back, he didn't notice, she had already gotten it messy and dirty again.

Then came that one day. Her first expedition outside the walls since she had lost her memories. The setting of the battle was that abandoned town which was where her memories had been lost, but no one told her that.

"YAHOO!" she shouted, swinging around and attacking the titans with a grin on her face, goggles securely in place. One after another fell to her blades, but Levi could tell that she was using too much gas, being reckless, more so than usual. Then it sputtered and went out.

She fell.

She managed to use her gear to secure a safe landing, breaking no bones and only gaining minor scratches.

Everyone else was distracted, there were titans everywhere, and they were too busy cutting them down to notice that Hanji was out of gas and far from the supply carts. She weaved in and out between titans, counting on others to kill them as she headed to those carts, hoping to make it in time.

"Come on shitty glasses, you can make it to that damned supply cart, it's not that far away anymore." Encouraging her seemed like the only thing to do, even if it fell on deaf ears.

Sadly though, she was stopped by a titan in front of her, and so close to the supply carts too. Moblit saw this though and kept that titan busy, allowing her to continue. If not for the titan behind her that was. It reached down, extending a hand to pick her up.

"HANJI!" Fuck no! Levi refused to let her get caught now, refused to let her die merely by being eaten. He hurled himself at her body, forgetting the fact that he was merely a ghost.

"GET OUT OF THE WAY OF THAT HAND SHITTY GLASSES!"

Hanji turned around, sensing the hand coming, but it was too late to get out of the way.

And then.

Push.

She somehow avoided the gigantic hand that had previously been bearing down upon her. For some reason she had also fallen on her ass and was about 30 feet away from where the hand had smacked down.

It had happened in under a second, but Moblit had seen, oh he had seen alright. The way he would later describe it would be, "It was as if she had just been pushed down, but not down per say, not up either, more like sideways, it was if she had temporarily flown and then landed safely."

In any case, she managed to reach the supply carts quickly after that, Moblit guarding her back. She refueled and got back out there to fight. Meanwhile, Levi was stuck staring at his hands because he had just pushed Hanji out of the way of a titan's hands. Ghosts should not be able to shove people, much less 30 feet away from where they were originally.

end part 4

Some poltergeists can be dubbed "guardian angels" by the living, while others will be called "evil spirits," it all depends on the poltergeist's emotions and will when interacting with the living realm.