After the cliffhanger of Chapter 89 in "Attack on Titan," Chapter 90 promises some exciting return as it might bring down the curtains on Armin and Mikasa's past. The illegal book of Armin's grandfather could also feature in the upcoming chapter.

It is speculated that "Attack on Titan" Chapter 90 might unveil the secret of Armin's ancestors, claims Tripped Media. According to the site, the previous chapter saw Eren suddenly realizing that he might have the ability to use the King's power. This was an indication that the royal family is not the only ones who can use it. Eren also revealed that he connected with Dina Fritz when he attacked her Titan form with his bare fists.

In Chapter 89, the "Return to Shiganshina" arc came to a tragic but satisfying end. Viewers saw Armin acquiring the Colossus Titan power. The one who was considered as one of the weakest soldiers proved himself and his intelligence saved the whole Scouting Legion from defeat. He also made it clear that he was capable of combat and his sacrifice was instrumental in the capture of Betholdt.

The battle between the two had an adamant Armin who kept holding on to his dream of seeing the ocean. He shared his dream with Eren as well and both went on to explore the outside of the walls. He often used to tell Eren about the body of water, carrying an unlimited supply of salt that he saw through the book of his grandfather.

Speaking of Armin's grandfather, he possessed an illegal book about the world 100 years ago and handed it over to Armin, claims Fandom (powered by Wikia). It was his grandfather who took care of Armin and his parents were never shown in the anime. What one knows is that they died while trying to escape beyond the walls which leads to the question that why would they do it if they knew that only Titans lived beyond the walls.

Well, the answers to all the secrets are expected to come out in "Attack on Titan" Chapter 90, that is scheduled to release within the next two weeks.