Authors note: This is what I wanted to happen in the season 2 finale.
A reason to fight
In the middle of battlefield where the survey corps we're battling the Titans that were thrown by the armored Titan, trying to stop them from escaping with Eren. Eren himself was on his knees on the ground next to Mikasa as the smiling Titan finished eating Hannes. He had tears in his eyes as he screamed.
"I'm sorry mother, in the end I wasn't strong enough, nothing's changed" said Eren as he closed his eyes.
"Eren " said Mikasa, Eren looked at Mikasa who had tears in her eyes as she smiled at him, "Stop that isn't true". Eren looked surprised as the battle behind them continued. "Listen, thank you" she said.
"For fighting, for always standing by me, thank you" she said as she got closer to him, "For showing me how to live, thank you" as she then grabbed the red scarf that he wrapped around her so long ago, "My scarf" she said looking at scarf then looking back at him smiling at him with tears in her eyes, "For always wrapping it arm around me, thank you".
Eren was surprised from the way she was speaking. Then quickly Mikasa kissed him on the lips with her eyes closed. After the kiss she continued to look at him with a smile on her face, "I love you Eren" she said.
Eren then thought, "No we're not going to die here today". He stood up from the ground facing the smiling Titan, "Mikasa, I will always wrap your scarf" he said looking back at Mikasa who seemed surprised, he then looked back at the smiling Titan as it began to reach its hand out towards them, "Always and forever, that's a promise" he said as his hand fully regenerated."I won't let you kill anyone else I care about" he tought as he clenched his fists and punched the Titans hand.
The other Titan shifters in the area felt like an electric shock go through their body's. The smiling Titan brought its hand back when Eren screamed and sent his right fist at it again. After he did a Titan jumped over him and onto the smiling Titan, Eren looked surprised and he ignored it as he got Mikasa onto his back since she was injured. He started running way as the other Titans on the Arabs stopped fighting ting the sours and started going towards the smiling Titan as they began to rip it apart and eat it.
"What's going on, they're eating it" said Mikasa surprised from what was happening as she held onto Eren.
There was the sound of foot steps and Eren looked the direction from the sound was coming from. It was the armored Titan with Bertolt still standing on its shoulder.
Eren then stopped running facing the armored Titan, "GET AWAY FROM US" shouted Eren, the Armored Titan and Bertolt felt the Elctric Shock go through them again, "YOU MONSTERS, ILL KILL YOU WHERE YOU STAND" he shouted.
The Titans that had just finished devouring the smiling Titan started running towards the Armored Titan and Bertolt.
"What's going on" said Eren, then Armin who was on a horse, Jean was behind him unconscious on the horse and Armin was holding onto another horse that was next to his, "Armin" he said.
"Can you ride" said Armin.
"Yeah" said Eren.
"Then hurry" said Armin.
Eren with Mikasa on his back got onto the other horse when they heard commander Erwin shout, "This might be our only chance, all soldiers retreat".
The scouts on their horses rode away from the Titans, except Ymir who was still in Titan form went back to help the armored Titan and Bertolt. No one knew why she stayed behind. The sky had now gotten darker as the scouts continued back to the wall, Eren looked into the sky thinking about the events that had happened to him over the last few hours. He was sad because of all the people who had died just to rescue him. He felt Mikasas head on his back as she held onto him and so Eren put his right hand over Mikasas right hand.
Eren now realised he has another good reason to destroy all the Titans. It was to make sure he and Mikasa would have a future together. After she kissed him he realised that he was in love with her aswell. Mikasa is his reason to keep on fighting.