They were out on mission when their squad was targeted by five fifteen meter class titans. Eren was already injured from a previous encounter so was told to stay back. He would have listened had Captain Levi not been grabbed. Eren didn't think just shifted, only one goal in his mind. Save Levi.
His enraged scream sounded as he ripped the arm holding Levi off the titan before then biting into the things neck before gently opening the severed arm's fingers freeing a wounded Levi. Levi manages to get to the carts himself as Eren fought off the other Titans. Once the titan threat was dealt with Eren ripped himself from the neck and fell exhaustedly to the ground. He was placed in the cart next to Captain Levi who checked over the younger male. He was healed of his injury but seemed to tired from the energy of transforming so soon after the last time. They made their way back into the safety of the wall. The angry jeer of the civilians fill the air as the wounded carried the dead. One particularly stupid civilian made to grab the wounded Captain out of anger but before Levi could react a hand grabbed the mans wrist.
"You will not touch him" Eren growled and shoved the man back. Levi looked at Eren while trying to hide his shock.
'When did the brat even wake up?'
Eren said nothing else but hand rubbed his temples as if he had a headache before laying back down. Once they arrived back at HQ Levi got patched up while Eren slept on the cot near by. He had noticed the worried glances the woman set toward Eren and frowned.
"Why do you look worried four eyes."
"Oh I'm not worried. Just hoping Eren wakes up soon. He needs to eat after all."
"OI Brat!" Levi called and like magic Eren's eyes open groggily.
"Yes Captain Levi?"
"Four eyes says you need to eat."
Eren looked at Henge and rose an eyebrow at her. She gives an awkward smile and hands him some rations which he obediently ate. Eren slept until the next morning.
A week passes and Levi notices Eren seemed have taken to making him tea every night. Even managing to make it exactly how he likes it. Seemed to be more attentive in training and seemed to take cleaning more seriously. Then during training they were practicing hand to hand. Eren was facing Jean which apparently was a very bad idea as they fought far more aggressively then called for. Eren after taking a particularly hard blow started coughing and to Jean and others horror Eren coughed up blood.
"Holy shit Eren!"
"I'm fine, I'll heal".
"Yeager go lay down till you do, can't have you coughing up blood."
He just sighs and leaves.
"Seriously Cadet this was a spar, you don't hit a comrade so hard he coughs up blood. What were you thinking brat!" The captain snapped angrily.
"I...I didn't think I hit him that hard sir."
"Your mucking out the stalls for a month Cadet."
"Yes sir" Jean mutters before everyone was dismissed.
Levi heads toward his quarters when he hears voices.
"Henge, stop fussing i'm fine."
"Eren this is the sixth time this month."
"Eren...Maybe you should tell them. They should know."
"Henge, you know I can't, Specially not Captain Levi."
"Don't you think they will take it harder after the fact if you don't?"
"Let them focus on what matters. We are so close to winning this war Hange, Almost all the titans are dead. Only a few more missions and we win. Let them focus on that."
"But Eren".
"NO Henge."
"Will you at least tell Captain Levi how you feel?" Henge teased trying to lighten the mood.
"Henge" Eren whined making her laugh.
"Fine fine, but you make it so painfully obvious that you love him."
Levi quickly goes to his office.
'Eren loves me? Seriously...but he is keeping that and something else from me. Is Eren sick?'
Another month Passes and this time Levi could plainly see the signs of Erens feelings for him. His lingering gazes, the happy smiles, the odd protectiveness. But he also saw that Eren would often get headaches or dizzy. They went on two more missions in the past month and only a handful of titans remained. One last mission and Humanity would finally be free. The night before the last mission he hears a knock at the door.
"Come in."
Eren steps in sadness in his eyes.
"Captain, its time I tell you something you need to know."
"What is it."
"Soon after this mission...I'm going to die."
Levi freezes in place. His eyes widen in shock.
"W...what".
"The titan shifting power is destroying my body, Captain, With every shift it brings me closer to death. Hange has been looking for a cure but...unless she finds one soon. My body will be beyond saving."
"Eren..." He whispers pained. Before he could stop himself he pulls the boy into a searing heartfelt kiss. He feels the younger male tense from shock before relaxing into the kiss.
"Don't stop fighting, please, please try to survive. Try to hang on. Please."
Eren wraps his arms around Levi.
"For you I'll never stop fighting. I love you Levi, I don't want to leave you. But the odds don't look good for me Levi. Even if I survive. Even if Hange cures me, there is not guarantee the courts are going to let me live."
"I wont let them Kill you" Levi growled.
Eren looked at Levi with a sad understanding smile.
"Then I make a promise to you Levi. Should I pass. I vow to find you in the next life. I also promise not to be to scared to tell you how much I love you."
Levi kisses Eren fiercely.
The next morning Levi wakes next to a very nude Eren in his bed. He gives a whisper of a smile before gently waking him.
"It's time Eren".
They both get ready for the Mission.
"Eren no shifting, not unless you have no choice" Levi orders.
Eren nods and gives him a reassuring smile before Erwin starts his speech.
"THE FINAL MISSION FOR HUMANITY BEGINS NOW!"
There were cheers from Soldiers and Civilians alike as the scouts speed through the gate.
The mission was smooth as they executed the remaining Titans. The final Titan killed on a beach.
Eren stood next to Levi, Armin and Mikasa looking out of the shimmering shifting waters of the ocean they always dreamt of seeing.
As Mikasa and Armin along with the others of the Levi Squad Celebrate and play along the waters edge. Eren lays under a tree. He coughs and notices more blood and sighs. He knew it was time.
"Levi, Love." Levi looks at Eren and sees the blood.
He gains a pained look.
"It's time isn't it?"
"It is. A human was never meant to hold this ability long Levi." Eren gives Levi sad smile.
"Call them over".
"All member of Squad Levi over here now!" Levi yells sorrow making his voice crack as he grabs Eren's hand. They come over and notice their Captain looked lost and upset, Eren sad and pained. Even Erwin and Hange come over. Eren grips Levi's hand like a life line as he speaks to his friends and comrades.
"I have been keeping something from all of you well except Hange but I told her not to say anything."
"The titan shifting ability, Is destroying my body, I knew before the start of this mission I would not return beyond the wall. I'm Dying and I only have a few moments." He pauses letting the words sink in.
"Mikasa...You were always like a sister to me from the moment I saved you from the slavers. Stay strong and live well. Armin, You are my brother in all but blood. A genius mind, put it to use yeah." The group was tearing up Armin was openly sobbing.
"Hange I know you tried your hardest to find a cure. Don't feel bad. A human was never meant to hold this power. It was inevitable. Connie, the joker of the squad, always making people laugh and lightening the mood, this group of misfits is going to need that in the coming days."
"You can count on me Eren" Connie said tearily.
"Sasha, you have far more land to hunt and farm. Make good use of it ok?"
"You got it" She says sadly.
"Jean...We fought a lot, never really saw eye to eye but. Your strong and brave. Smart and as of late as stubborn as me. Don't back down Jean. Never Back down."
"Fight till the last man right Eren?"
"You got it. Erwin, It was an honor to fight for humanity, you are a great commander. A hero. Thank you."
"No Eren you're the hero, turned the tide of the war. So thank you. It was an Honor to fight this war with you."
"Levi, It was an Honor to fight under your command, even if we met in rather unfavorable circumstances. I love you Levi and though I am passing, Know I will hold true to my vow, and find you in our next life. So this is not Good bye, Just a see you later."
"I love you too Eren, I don't know when but... but some how you wiggled your way into my heart without me even noticing. I'll be waiting for you Brat so don't keep me waiting long."
Levi kisses Eren softly pulling away.
"Levi one last favor".
"Anything".
"Smile for me. I don't wish to see you sad."
He smiles softly at Eren and then only moments later Eren's hand goes limp in his own. Eren was gone. For the first time in many years Levi lets himself cry.
The march back to the city was met with a mix of cheers of victory and the silent sadness of the Levi squad. Later Erwin addressed as big of a gathering of people as possible.
"Today is the day we won this war, Today we are free of the titans and it is all thanks to one man. One who at the expense of his own body. Suffered in silents to give us the weapon and the hope to win this war. The Hero Eren Yeager now fallen. It is thanks to him we are free and though he is no longer with us, His memory will live on the hearts and minds of his friends and comrades as the true hero of humanity and though he is gone the hope he brought into all our hearts will live on as humanity grows and reclaims the lands which was lost to us for so long." They bring out Eren's body still dressed in his soldier uniform and placed him on the wooden pier. Levi comes with a lit torch and lights the wood. Before joining all the soldiers then as one all the Soldiers Salute in honor of the fallen hero. Civilians bow their heads in respect and Levi could have sworn among the flames stood the spirit of Eren saluting with a proud smile before fading away.
After that day a statue was erected in Eren's honor depicting Him in both Human and Titan form standing back to back. The human side standing in his soldier salute. On the mental plate was inscribed.
'In honor of Humanities Hope and hero Eren Yeager. Gone but never forgotten.'
-Time skip three hundred years-
Levi stood in front of the historical statue. Like he has done every day for the past week since he regained all the memories of his past life. He looks up at the depiction of Eren. Pain in his heart at a love that was lost before it could even truly bloom.
"You know Captain, I always keep my vows".
The familiar voice made Levi spin around in shock to see Eren standing their with a soft smile.
Levi give a tearful smile.
"So it seems but I haven't been your captain in a very long time."
Eren chuckles and pulls him in a firm passionate kiss.
Once Eren pulls away he rest his forehead on Levi's.
"I love you Levi".
"I love you Eren".
"Ready to truly begin our lives."
"God more then ready."
They share another kiss before walking off hand and hand. Smiling bright because now...now they can be truly happy and free.