Spoiler alert: This article contains spoilers for Attack on Titan.\n\nThe end of an era is upon us as Attack on Titan returns to round out the final season. The battle between the Marleyans and Eldians is about to reach a tipping point as Eren Yeager goes rogue in his misguided quest for freedom. But even fully-armed soldiers, skilled Marleyan Titans, and the remaining vestiges of the Survey Corps couldn't possibly prepare anyone for the Rumbling.As an anime, Attack on Titan is an international smash hit. The story follows Eren Yeager and his friends as they enlist in the militaristic Survey Corps to defend their walled-off cities from giant, man-eating Titans. As their battle rages on and sacrifices are made, they come to realize the horrifying truth of the world and their place in it. The end of a war centuries in the making is fast approaching, but the Rumbling will most assuredly bring a decisive end to the battle one way or another.What is "The Rumbling" in 'Attack on Titan'?In Attack on Titan, history is no stranger to the cataclysmic event of the Rumbling. Years before the events of the series, tensions between Marley and the Eldian Empire reached a boiling point. With the Eldian Empire forced into their walled cities on Paradis Island, King Karl Fritz sought to ensure the safety of his remaining subjects.He constructed the walls out of Colossal Titans and issued a warning to Eldia's enemies. If their island came under attack, they would use the power of the Founding Titan to awaken the Titans in the wall and lead them as they walked across the land and trampled everything in sight under their might. \n\nThough intended as a hollow deterrence of war, it proved effective. No outside nation declared war on Eldia in over a century.But as the events of the series took place, the Survey Corps and their international allies looked to the Rumbling once more, hoping to unleash on as a small scale as an open-faced deterrent. By having Eren, the current host for the Founding Titan, come into contact with his royal-blooded half-brother Zeke, he would attain the power to use the Rumbling. But given Eren's current mental state and Zeke's ulterior motives, the Rumbling becomes far more than just a deterrent.The anime itself knows that the Rumbling is imminent."Rumbling. Rumbling. It's coming." As per the words of the newest opening for Attack on Titan: The Final Season, the Rumbling is all but assured to occur. With Eren defying the expectations of both Marley and his own Eldian comrades, he's prepared to leave nothing but destruction in his wake. Years of war and sacrifice have weighed heavily on him. With a potential army of Colossal Titans at his disposal, there's far more at stake than just the war between Marley and Eldia.New episodes of Attack on Titan: The Final Season stream every Sunday on Crunchyroll and Funimation.