The time was midnight and the night sky beautiful. Parts of the full moon were covered by dark clouds. Within the capital of Paradis, a Nineteen-year-old Eren Yeager roamed throughout the entire castle Mitras for an entire hour. Reflecting on all of his past mistakes he made and what he had done in his own timeline. He had pushed himself away from his closest friends and forced the entire world to not only hate Paradis, but to also made them want to eradicate all Eldians on the island.

Then, Eren Yeager had stopped and looked at a window. He noticed that the clouds were covering the full moon in the sky. "What have I done?" He sighed, disappointingly.

Meanwhile, Frieda Reiss and Ymir just stood in the back of the castle yard, waiting for Adult Eren's arrival. Ymir stood and her body language said that she was getting tired of waiting. She crossed her arms and repeatedly tapped her right index finger on her left arm.

Flashback

Earlier that day, Adult Eren had approached Ymir in her room and told her about time traveling.

"Meet Frieda and I at the back of the castle yard at Twelve O' clock, midnight. If you don't, we'll leave you, behind." Eren said.

"Okay, fine. I get it. I'll go on this little time traveling adventure with you." Ymir said.

"Good." Eren then turned toward the door and begun to leave Ymir's room.

End Flashback

"He's late." Ymir muttered.

"Calm down, Ymir. Eren's just taking care of a little business." Frieda said, reasoning with Ymir.

"I don't get him. Like, what's the point? He tells us to be here at midnight-but he can't even show up to the rendezvous point, himself?" Ymir questioned.

Frieda smiled. "Don't worry. Eren will be here, soon."

Meanwhile, a Ten-year-old Mikasa Ackerman had slept in a room, alone. She wore a white night pajama dress that nearly resembled the dress that she had worn when she was kidnapped in, a year prior... a year prior. She lied on her right side. Her face was facing the wall and her back was facing the front door. Her red scarf had been properly folded and was placed next to her head.

Within the next minute, Mikasa suddenly heard the sound of the door creaks-meaning that someone was opening her door. She then heard footsteps getting closer and closer to her. She slowly opened her eyes to see a shadowy figure over her on the wall in front of her. When she did, she silently gasped in shock. then, she quickly lifted her upper body upward and faced the front door-only to be met by a Nineteen-year-old Eren Yeager kneeling before her while she sat in bed.

"It's okay. It's okay. No one's going to hurt you. I promise." Adult Eren had assured Mikasa.

Mikasa made eye contact with Eren for a moment, then calmly sighed. "Mister Kruger..."

"Sorry, if I scared you." Eren apologized.

"Is there... something wrong?" Mikasa asked.

"No. I wanted to check on you and see if you were alright?" Eren paused, when he visualized a fifteen-year-old Mikasa Ackerman.

"I'm fine." Mikasa nodded. "Thank you."

"Good. And also... I came here, because I thought that you would want to hear a story?" Eren said, thinking that Mikasa might listen to him.

Mikasa blinked, once. "A story?"

"Yeah. The story is about a person I know of. Someone that I care about. And she is one of my closest friends in the world." Eren, then, in the back of his mind had visualized a fifteen-year-old Mikasa Ackerman wearing a Survey Corp. uniform and wield vertical maneuvering blades.

"Miss Frieda?" Mikasa guessed.

Eren smiled and shook his head no. "Not her. Another person that I care about. Her name..." Eren paused in front of Mikasa. "I'll reveal her name at the end."

"Hm? Her name?"

"She was very strong. She was very pretty. And she cared a lot about her friends and family. I've known this person, since I was nine years old. We lived under the same roof, together. And we joined the Military, together. And every time I would get in trouble, she would step in and try to help me as best she could." Eren stated.

"Your friend sounds amazing." Mikasa said.

"She is." Eren told an Adolescent Mikasa Ackerman. "But because of her amazingness, I began to feel jealous of her. I wanted to do my own thing-but she always got herself involved and protectively of me. And whenever... I would constantly push her away."

Brief Flashback

Eren bumped his head with Mikasa in the year, Eight-Fifty within Trost District.

"Enough, Mikasa! We don't have time for bickering, so get it together! Humanity is on the brink of extinction-so act like a proper soldier!" Eren yelled at Mikasa.

Mikasa grasped her forehead, then sighed in a sad tone. "Sorry. I guess my head isn't thinking, right."

End Brief Flashback

"I never apologized to her for those incidents-except when she got hurt. The real reason why I did treat her, poorly, was because I was jealous of her. She was good at so many things. She even graduated at the top of our class. And when I tried to compare myself and catch up to her... she would always walk a step further ahead of me." Eren stated.

"Did your friend ever know you were jealous?" Mikasa asked as she listened to Eren's story.

"I admitted it." Eren told Mikasa. "But no matter how many times I push her away, she would never leave my side. She would help me get better in the long run and thought of me as her last remaining Family."

"Family..." Mikasa muttered.

"Yes." Eren nodded. "Family had always been her duty. And her name. Her name... was Mikasa Ackerman." Eren then thought of Mikasa Ackerman when.

Brief Flashback

In the year, Eight Fifty-Four, Eren Yeager had attacked Marley with his Attack Titan. Which would soon lure out the Warhammer Titan. Mikasa Ackerman had interfered after Eren lost the head of his Attack Titan. She stood on top of where the head of Eren's Attack Titan used to be and glanced down at Eren with worry.

"Eren. Come home." Mikasa told Eren.

End Brief Flashback

The Adolescent Mikasa gasped. "There's another person named Mikasa Ackerman?" Mikasa felt confused as she pointed toward herself.

"Yes. But at the same time, no." Eren had explained.

"I'm kind of confused, Mister Kruger." Mikasa said, honestly. Not understanding Eren.

"What I'm saying is that the Mikasa Ackerman I just described will be you, one day." Eren said as he pointed at the young Mikasa Ackerman.

"Me?"

Eren nodded.

"How do you know that I will be this person when I grow up?"

"I know, because I watched her grow to be an amazing person. I know, because I watched her grow into becoming one of the strongest soldiers in the walls. I know, because I'm from the future." Eren stated.

"The... future?"

"That's right. And I'll be completely honest with you. My name isn't Kruger..." Eren reached for the back of his head and begun untying his hair. "My real name..." Eren had untied his bun and let it fall down to his shoulders. "Is Eren Yeager."

Mikasa' eyes had grown big in shock after hearing Eren. There's been nothing but utter silence for half a minute. She then looked down a bit and gripped part of the bedsheets. "So, it's true. You really are Eren."

"You knew?"

"No. But I always felt that there was some kind of connection, between you two."

"I get that, sometimes." Eren said.

"When I first saw you leave Shiganshina with the Survey Corp. I immediately knew that you two had kinda looked alike-with the brown hair and green eyes and the skin. And now that you've said it..." Mikasa then extended her left hand out toward Eren's face. And in the next moment, she touched Eren's right face.

Adult Eren did not grab or stop Mikasa from touching his face.

After a moment, Mikasa then stopped after feeling his upper right facial structure and slowly pulled back her own hand.

"Better?"

"You feel just like the other one... except that your face is harder" Mikasa stated.

"That's what happen when you get older. Not only will your body-but your facial structure will change as well." Eren smiled, then looked over to what' next to Mikasa. He stood on his feet and grabbed Mikasa's scarf.

Mikasa gasped when she saw Eren reach across her and grab his scarf. "W-what are you-" And suddenly in the next second, she felt her scarf be wrapped around her neck by the Adult Eren.

"There. That will keep you warm." Eren said after he finished wrapping Mikasa's red scarf around her face.

"But, why?"

"Because. I once made a promise to wrap that scarf around you as many times as you want." Eren told Mikasa.

Flashback

In an unknown land, the Survey Corp. were battling against a horde of Pure Titans and also, battling against the Armored Titan. Hannes had failed to avenge Carla Yeager and had been devoured by Dina Yeager as a Titan. And Eren Yeager begun to lose hope, until Mikasa begun to thank him. But Eren refused to give into death. He chose to keep fighting, despite the odds.

"I'll wrap that scarf as many times as you need to. That's a promise!" Eren said as he faced Pure Titan named Dina Yeager.

Brief Flashback

In the next second, the two of them then hugged. "Please, be safe, Eren." Mikasa said as her eyes watered in relief. Her arms were wrapped around his neck.

"I will. I'll come back as many times as you want." Eren replied as he wrapped his arms around her upper back.

"Please, treat the other me, well." Mikasa said, referring to her older counterpart.

"I will."

In the next three minutes, Adult Eren then left Mikasa alone in her room. Quietly closing the door behind himself. Afterward, he then walked toward the hallway door where his younger counterpart had slept in all alone on the other side of the hallway door. Adult Eren quietly opened the door and saw his younger counterpart sleeping soundly in bed. His body was facing the ceiling.

Eren stared at his younger self who slept in bed. As Adult Eren continued to stare, he then thought of what happened in his previous timeline. Adult Eren revisualized his mother, Carla be eaten by Dina from a distance. "Take care of mom and Mikasa while I'm gone, okay?" Adult Eren said, then walked back to the front door. He slowly opened it-which earned noises coming from his younger counterpart. The ten-year-old Eren was still sleeping.

By the time Adult Eren had left his younger counterpart by himself in the room he was sleeping, he was met by Grisha Yeager in the hallway.

"You're leaving, aren't you?" Grisha asked.

"Yeah. I am." Eren nodded. "I need to go back and see my timeline-since I've left. I need to know if "My" Mikasa and Armin are still alive. I need to know if everyone else is, okay?" Eren said as he then thought of last time, he had met them. He made Mikasa cry and had physically assaulted Armin in a restaurant.

Grisha stared at his adult son and thought of something, different.

Flashback

In the year, Eight Thirty-Two, Grisha Yeager and Eren Kruger had stood on top of a wall on the edge of Paradis Island. Grisha was depressed after watching his first wife, Dina be forcefully turned into a Pure Titan.

"If you want to protect Mikasa, Armin and everyone else within Paradis... then, don't give up. Keep fighting." Eren Kruger told Grisha.

"Mikasa? Armin? Who are they?" Grisha asked.

Eren Kruger paused. "I don't know. Whose memories are these?"

Brief Flashback

"I see." Grisha muttered. Then he placed his left hand onto his adult son's right shoulder. "All I can do is wish you, the Queen and Ymir the best of luck, over there. While you're gone, I'll make sure that no one harms our family, this time." Grisha said.

"Thanks, dad. I don't plan to be gone that long." Eren replied.

A few minutes pass by and Eren had finally rendezvoused with both Frieda and Ymir outside of the castle yard.

"You're late!" Ymir stared daggers at Eren, which he ignored.

"Sorry. I just finished taking care of business." Eren said with a chill smile on his face.

"Were you able to speak with Mikasa?" Frieda asked.

Eren nodded to Frieda. "I did."

"And... did visit your younger self?" Frieda asked.

"I did." Eren replied.

Frieda clasped her hands, together. "That's great!"

"As much as I hate to interrupt this-chitchat between you two, but can we get going, already? I'm starting to get chills!" Ymir shivered a bit, due to the night cold weather. She crossed her arms.

Eren nodded. "Fine. Grab on." Eren said, then turned his back toward his two fellow Titan Shifting companions. Both Frieda and Ymir had grabbed clung Eren's shoulders. "Ready?"

"I am, Eren." Frieda replied.

"Yeah. I'm ready." Ymir said.

"Hang on, tightly." Eren said, then in the next two seconds... Eren closed his eyes and exhaled, then open them with fire inside green raised his left hand in front of his face and sunk his teeth in it. After biting his own hand, Eren's entire body began to glow the color of white, rather than yellow. A white lightning from above had struck the Titan Shifters, causing the three Titan Shifter to disappear from thin air.

Author's Note: This had taken a little longer than expected. But now we're about to see what happened to Eren's old timeline after Eren disappeared. :)