TROST, YEAR 850

Is this the end? Eren thought as he was being swallowed by the titan. The seas…the burning water…the vast deserts… will I not see them all ? Will I not be able to avenge my mother?
This line of thought continued until he reached the titan's stomach. Without any digestive organs, unlucky victims who didn't die when the titan ate them will soon die of the extreme heat.
"No….I can't die here! NO!"
Eren tried reaching out, tried looking for a way out…but there was none.
"Shit! I won't give up… I won't… I won't!"
"Is your will that strong, Eren Jaeger?"
A voice penetrated the silence of the Titan's stomach.
"What? Who's there?" Eren looked around, and saw a small creature. It was white, and it looked at him intently.
"Who are you?" Eren asked.
"My name is Kyubey, Eren Jaeger. Now tell me? Is your will strong enough? I can grant you a wish… any wish you want. I want you to know, however, that this carries a risk. Few who have made a contract with me have been successful. Many… they were not strong enough, and they ended up in the worst state imaginable."
"Of course I'm strong enough!"Eren said. He didn't know if he's dreaming or if this is real, but right now he's willing to do anything to survive.
"Now tell me, Eren Jaeger…what is your wish?"
"I wish to have the power to eliminate every titan with my own hands!"
Kyubey paused, then said: "Your wish is granted, Eren Jaeger…."
There was a flash of light, and Kyubey was gone.
That's it? Eren thought. Maybe it was just a dream- he had no more time to think, as the wish came into effect, transforming him into a giant titan.

-MONTHS LATER: INSIDE WALL SINA
Kyubey watched as Eren and Annie fought in their titan forms, neither caring about the damage they were causing to the city. "I'm not sure this method is more effective in our goal of stopping the heat death of the universe."
"We understand, Kyubey," said a fellow Incubator, who was worlds away. They were using telepathy. "We'll be sending someone else there. We will send you to another world, where your abilities will be put to better use. We have found the perfect way to gather energy to prevent the heat death of the universe."
"I understand." Kyubey held on last glance at the two combatants. He knew both fighter's strengths and weakness, and why not? He's the one who gave powers to both of them. The Incubators still do not know why with most of the humans, the process of making the contract goes horribly wrong, transforming the person into what the humans of this world call Titans. Another mystery is why humans like Eren Jeager and Annie Leonheart were able to control this power. "I don't understand at all," Kyubey said. He turned his back while the battle raged on, leaving just as Eren was about to land the finishing blow.

Note: I'm not sure if the battle of Trost occurred at 850, and not sure when the battle in Wall Sina occurred either. If any of you know, please comment in the reviews.