The final season of Attack on Titan is slowly answering every hanging question to give the anime a proper ending. As everyone is probably thinking how each storyline will come to a close, it reveals the truth behind the Wall Titans' longstanding mystery circling the walls.

Attack on Titan Season 4 Episode 5, "Declaration of War," saw Eren and Reiner's reunion, while Willy Tybur's delivered his war declaration. As the title suggested, this episode started the war, and the Eldian noble revealed the truth about the nation's history and the Wall Titans.

He said King Karl Fritz used the Founding Titan's power to gather a huge number of Colossal Titan to use them build the walls that would surround his people. These walls were named after Ymir Fritz's daughters, Maria, Rose, and Sheena, while Ymir played as the mother of all Titans.

The Wall Titans are different from the regular Colossal Titan. They can harden the top layer of their skin and the entirety of their bodies.

With this skill, they lined up their hard bodies 100 years ago to create the wall protecting the Eldia. Tybur continued to reveal King Fritz made a pact with the Founding Titan when he built the wall, promising "renouncing all future war," CBR noted.

He then warned that millions of Colossal Titans would be unleashed if an attack were made upon the island. This is the reason why Marley never dares to attack the place as it may ignite an "apocalyptic" war, also called The Rumbling.

In Attack on Titan Season 4, Tybur called Eren's name, saying he is the reason for the recent uprising on Paradis Island. He even revealed Eren has the Founding Titan, meaning he can unleash The Rumbling anytime.

So, the war on the island also means a war with Eren. The Wall Titans are a great danger not just to Marley but to the world and the Paradis Island people. Now, it is a big question if Eren will ever unleash The Rumbling or take another path.

Talking about the series' end, Hajime Isayama himself revealed he is unsure if the final season's ending would be "happy or not," per Comicbook. With Eren's drastic change from a protagonist to the main villain, he will surely try to get the better of his enemies.

The next Attack on Titan Season 4 episode, "The War Hammer Titan," will be out on Monday, January 18. As the Attack Titan continues to run amok, resulting in several deaths, the War Hammer Titan appears to face Eren.

What else do you expect to happen in Attack on Titan Season 4? Share your comments below.