All good things must come to an end, and the end is in sight for "Attack on Titan." The anime adaptation of Haijime Isayama's groundbreaking manga will come to a close with the third part of its fourth season, which is slated to premiere next year. True to its title, the series features a battle against the monstrous Titans; hulking giants who wander the Earth and devour living creatures. Eren Yeager, having witnessed the death of his mother at the hands of a Titan, has resolved to kill the beasts — a mission that's made even harder by the fact that he can transform into a Titan himself. I've been drawn to the series due to the battles against the Titans, as well as the dark storytelling. Trust me when I say this is a series that rivals "Game of Thrones" or "Breaking Bad" in terms of darkness, but hews toward the latter in terms of plotting and payoff.

Throughout "Attack on Titan," more information about the Titans is revealed including their origins, and Eren and his fellow members in the Survey Corps encounter different variants of Titans. Here is a guide to the different Titans that appear in the series, and where they came from.

Their Origins

The first Titan to ever walk the earth was Ymir Fritz. Two thousand years prior to the events of "Attack on Titan," Ymir was sold into slavery when the nation of Eldia attacked her village and killed her parents. When Ymir was being hunted by Eldian soldiers after she accidentally let some pigs loose from the stables, she encountered a massive tree and upon entering it, fell into a sinkhole where a spiny creature entered her body and transformed her into a Titan. Ymir used her Titan powers to make Eldia one of the strongest nations on Earth. Eldia's king Fritz took her as his concubine, and she fell in love with him (despite the fact that he was responsible for murdering her parents and kept her as a slave — yikes). When Ymir fell in battle, Fritz ordered his daughters to consume her corpse so that the Titan powers would continue through his bloodline (double yikes).

Ymir's bloodline would eventually be divided among her descendants, giving them the ability to become Titans. A serum was developed that could unlock this ability, with Eren Yeager gaining his Titan powers after his father injected him with the serum.

Powers And Variants

Titans stand nearly 15 meters tall and look like the stuff of nightmares. Their faces are fixed in a rictus grin that would put the Joker to shame. They're mostly comprised of muscle, and they have an all-consuming hunger for human flesh. Isayama based the Titans' movements on an encounter he had with a drunken person at an Internet cafe; his inability to communicate with the other person helped inform the conflict between the Titans and humanity. Norse mythology also inspired the look of the Titans as well as their history; Ymir is the name of the Frost Giants' king in Norse myth.

And as if the Titans weren't frightening enough, there's the subspecies called the "Nine Titans." These were humans who inherited fragments of Ymir's power, allowing them to transform into Titans at will — while also retaining their human intelligence and new abilities. For example, the Armored Titan could harden parts of its body while the War Hammer Titan could make weapons from its body. And even more horrifying is the reason they consume humanity — they seek to regain their humanity.

Why Are The Titans Attacking?

You might be asking, "Well, why exactly ARE the Titans attacking?" The answer lies in the past: When Eldia reigned supreme, one of the nations under their thumb broke free. This nation, named Marley, then turned the tables and subjugated nearly all of the free world. Marley also came into possession of seven of the Nine Titans and used them to maintain their military power over the world. However, Eren Yeager slaughtered many of the Titans in Marley's possession and took their powers for his own, eventually launching an assault against Marley's forces using Titans under his command.

Whether you've been a fan since the first episode or you're looking to get into the anime, I highly suggest watching "Attack on Titan" to see how this story unfolds. It's a great intro to the world of anime, and the story and animation are top-tier. So are the fight scenes — watching Eren Yeager and his friends swing from ropes Spider-Man style in order to fight the Titans, or Titans brawling with each other, is a heck of an adrenaline dose.

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