The Fighter - Levi x Powerful Reader

Hidden Power

Your POV
     As I open my eyes slowly I see a glowing light coming from my shackles. The chains are releasing from my arms. Then it shines a very bright light, I shut my eyes tightly again. 'Huh? What's going on? Where am I?' I open my eyes slowly. All around was the colors of flame. I look around for anything.
"Hello?"
"Hello (y/n)"
"W-who's there? Who said that?" I look around again. Nothing.
"I'm the one you summoned."
"What do you mean?" The unknown chuckled.
"Answer this. Remember you said that you were more unique than the ones in your tribe?"
"Yes"
"Do you remember when you said that one day you will find that hidden power?"
"Yes I did."
"Well, I am that hidden power. I'm the one who is part of the flames. My name is Lighter. Nice to meet you." My eyes widen.
"Does this mean that you will be by my side from now on?"
"Till the end of time."
"What are you? Like what form are you in?"
"I'm just a voice, but it depends on you. I must tell that this will come some consequences."
"What are those consequences?"
"It's just one thing. That is if you have to put your energy a lot to use the power to the fullest. Are you up for it?"
"Yes I am. I have to do it for the others I could and couldn't save. Erwin. Isabel. Farlan. Levi."
"Alright. What will I be for you?"
"Wings. Like the Wings of Freedom but in flames, longer, and fast. I want to fly."
"Deal." With ending our little conversation, Lighter is now in my shackles always there when I need it the most. He goes into my shackles shining again when I first summoned him and now everything is back, the rain, the mission, the bodies. 'Yes. I have my now hidden power. I can finally be a use to the Survey Corps. I can finally save lives of others.' I thought as reality came back to me. The titan. The one who ate my whole squad and my best friends who were now dead. 'Isabel. Farlan. Everyone. This for you.'

Levi POV
     I'm still galloping on my horse. 'Shit. I don't think they already retreated. No flare has been shot. Come to think of it, are they all dead? No. Just a little more. Wait for me Isabel and Farlan.' I thought as I come across hearing a gun shot. I go to where the sound came from. I was on top of a hill, I see bodies everywhere. Blood staining the grass and body limbs everywhere. I hear whispering from my left.
"T-t-titan" a man says taking in all his energy for the warning. Dead. Gone. I turn back around because I know this was not right. Then it hit me. "How could've we passed each other?" I hit my horse's side signaling him to gallop at full speed I make him turn where all the bodies where I took a turn. My horse still at full speed, no titans have been seen it, my horse tripped on an arm making me fall and slide to the disgusting mud. I grunt from the impact and I closed my eyes a bit. I opened them again to only widen my eyes. Isabel's head, then Farlan's upper body, and (y/n). Next to her was a titan already dead. I get up and run up to her.