In the Attack on Titan world?

Chapter 27- the royal family and a new enemy

We hurried. I was uncomfortable and shaken but determined to find Eren.
We were in a cart racing towards where we believed that they were being held.

We planned it well. I would distract with singing from below as we filled the underground room with smoke. The others would fly above me, hidden within the fog killing Kenny's people. Then we could move on to find Eren and Historia.

Our plan soon set into motion. I began singing as soon as the smoke set off, it echoed around us.
I whistled. "Do do do do do, do do do do do, can you blow my whistle baby, whistle baby, let me know. I'm gonna show you how to do it and we start real slow. You just put your lips together and  you come real close. Blow my whistle baby whistle baby. Here we go." And I continued to whistle. It threw them off and I managed to make through a cavernous tunnel, I slunk I'm in the shadows where Kenny couldn't see me, or his men and then I made my way to behind Kenny. And I put a sword to his throat.
He flinched but otherwise he didn't move.
"So the new lass is quite sneaky." He joked. "And sly like a fox."
I moved the sword closer to his neck. "Make another joke and I will slit your throat like the dog you are." I growled.
I knew guns were trained on me I didn't care anymore. They had stolen my body and I would not get it back, but I could at least hurt them as they had hurt me. "Your men raped me Kenny, the ones in your payroll." He seemed shocked.
"They weren't on my payroll sweet. They are on Reiss'. And I apologise. That was not in the plan."
I dug the sword in tighter.
"It doesn't matter." I hissed. "He's got you in his payroll too so what does that make you?"
He seemed doubly shocked. He motioned for those at the top of the cavern to seal it off.
"I won't stop you sweet if its revenge you seek." Kenny said. "And none my team will stop you either."
I could imagine they would protest. "They had better not or I will come back and slit your throat." I hissed and ran off deeper into the cavern. It wasn't in the plan but if I could find Historia and Eren and get them out then the others I could alert with a song.
I carried on slinking in the darkness, until I heard voices. Then I hid in the shadows. What I saw chilled me to my very bones.
Eren was tied in chains,a piece of wood in his mouth to stop him from transforming. Stripped naked on his waist and arms in chains spreading his arms out. He was chained in a kneeling position. I could see his eyes wide and fearful.
I crept closer silently towards an man in late middle age and Historia. She was in a white dress, long and her eyes were wide in shock.
I listened. Apparently Erens father had lived outside the walls, and he had come into this very cavern one night and eaten her older half sister. One who had the power to control titans, and change the people within the walls and their memories.
Historia I knew was looking from Eren to her father.
It was a tense moment and then her father brought out a case. And when he showed her I was ready to leap but waited as he spoke. Inside he explained was the spinal fluid of one of her sisters, is she was to inject herself with this, she would transform and when she did she should eat Eren and gain back her sisters power as the only remaining Reiss heir. Apparently Eren's father had killed his other children and legal wife, in this cavern. Eren looked so shocked and disheartened. At that point he began to lose hope, head downcast, told Historia to do it when his gag had been removed, that he felt shame that his father had done this. While they were distracted I crept closer to Reiss. And when I was close enough kissed his throat with my steel.
"I suggest Reiss that you let your daughter go right now and with her my brother." I hissed. My words echoed around the cavern. Eren's head shot up.
"Layla?" He said in disbelief.
"Hey brother. See you got yourself in a bad situation again like always." I added, pushing down on Reiss' neck.
"Layla please." Historia begged. "He's my father."
"I am aware of that Historia, but there is something your father needs to hear." I paused, "you know the men you hired to store Historia and my brother up there in a warehouse? Nod if you understand me."
He nodded trying to avoid to slit his throat.
"Did you know that they were going to spoil their goods?"
Historia's face told me that if she had gone instead of me, she would have been ruined.
"No." He croaked. "They were ordered no harm was to come to my daughter should they find her."
"Well, if it hadn't have been me, your daughter would have been degraded and raped." I said making sure that last word rang around the cavern. "So be thankful that in turn it was mine and not hers they ruined." I hissed. "And all because they were in your payroll."
"My apologies."
"Apologies won't return what they took, and neither did killing them. So I suggest you let your daughter have a choice of leaving and of letting my brother go or so help me I will slit your throat where I stand." I tightened it slightly to prove a point.
He was silent but I could see his hand shaking, the vial and injection in his hand.
"Historia. What your father fails to tell you is the consequences. What do you think happens if you eat Eren?" I asked using the sword to keep her father silent. "You lose a friend. And not only will you lose a friend, you will lose a second. Because I will kill you where you stand if you turn Titan."
She shook. "You take that-" I pointed with her father and sword at the injection. "And you become like Eren, Ymir, Reiner and Bertholdt." I missed me. But she knew. "Is that what you want or is that what your father wants?To control the people in the walls. To prevent freedom?"
I let her think. She didn't notice her father inching the needle towards her skin and I jerked him backwards. "Don't even think about it. It's her choice. Forcing it on her because you are a coward is illegal." I hissed digging the sword in so that beads of red began to line the sword.
Historia realised that I just saved her from having her choice taken from her. She took the needle from her father and put in the case at her feet. Then she went and freed Eren. Moving her father around to save the exit I pushed him away from the case and picked it up myself.
He protested but I pointed my sword at his face. "I consider this payment." I waved the case at him. "For my body being ruined. As well as my brother and friends freedom."
"Please." He pleaded.
"No." I growled. "No one has the right to take someone's choice away from them. No one."
My hands shook. The after effects.
Reiss just stared at me, his eyes calculating. He must have realised he was beat, I hoped but I placed the case safe in my bag. In case he lunged for it. Then he gave up. He was a coward.
Historia helped Eren to his feet.
That's when the cavern began to shake.
What was going on?
I went to join them and then I looked down at Reiss. He had his hand poised in his arm- another needle and he injected himself. At that moment Levi and the others dropped in, rushing to where we stood from above.
"What the hell is going on?" He shouted above the din and the bright fire like light.
"He's transforming." I shouted back. "Into a Titan."
Shock filled the others faces. And we watched.
Reiss was an ugly Titan and he could barely lift his head from the floor.
This was the moment.
"Stop!" I yelled and my voice echoed around the cavern. It's power shooting through. "Stop!"
The Titan was growing, to the point where soon it would destroy the cavern in its wake.
"Stop!" I yelled again and it took effect this time. "You need to change back or you will bring this down." He chose not to listen to me.
"Get out now." I said to the others, "back the way you came. Go now."
"No Layla I am not leaving you again." Eren said.
"Get your ass out of here Eren." I said, my hands bringing my sword up. "I can only guarantee a few moments."
"No Layla, it will kill you."
"Then I died for humanity." I said. "I'm sorry my brother. But you need to go."
I sliced my palm. Smiling at them all.
"I'll see you on the other side."

And transformed.
I was quicker than Reiss. I was fully formed while he was still forming. My head reached the top of the cavern. The heat coming off Reiss would kill them. So I looked deep within me and called for a hardening ability-like Annies and Reiners. And my hands lit up. Ice like skin grew from them. I stood in front of the others. They wouldn't have time.
I had to protect them. So I concentrated hard, using the hardening ability to lock a pocket around us all.