WARNING: The following contains major spoilers for The Mandalorian "Chapter 13: The Jedi," now streaming on Disney+.

The Mandalorian's journey to find Ahsoka Tano on the world of Corvus led him to the gates of a village under strife. Calodan is under the thumb of Magistrate Morgan Elsbeth, a cruel imperial remnant once central to the Imperial Navy. At work under the eye of her new master, Elsbeth is protected not only by high city walls, but a cadre of sharpshooting soldiers and two unusually agile droids. Tall and slim, kept under wraps by cloaks, they're hard to identify at first. But the dialogue eventually gives them away, revealing the HK-series assassin droids are back in Star Wars canon.

The HKs' first appearance in the now non canon Star Wars Legends is also its most iconic. HK-47 was a party member early in Star Wars: Knights of the Old Republic, and quickly became the quotable, happily murderous heart of the game for many fans. HK-47 is passed off as a grim-looking protocol droid, and the ruse is revealed shortly after. As an assassin droid, 47 is a deadly efficient member of the team, and as a companion, he's morbidly funny, describing living beings as "meatbags" for him to kill.

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HK-47's memories and his true potential are only unlocked once it's revealed that he's back under his original master's command. As Darth Revan's personal assassin droid, HK-47's hostile behavior underwent further adjustments to make him even mouthier and dismissive of organics. Earning both notice and awards for Character of the Year, Hk-47 returned for the game's sequel, and even earned appearances during the Star Wars: The Old Republic MMO.

The Star Wars Galaxies online card game eventually gave the droid a "retirement" on Mustafar, but his influence wasn't yet gone. Chuck Wendig wanted to reference HK-47 in his canon Aftermath novels, but his pitch was shot down. However, he did include a unique B1 battle droid who bore the name Mister Bones with his own penchant for slaughter. At one point in the novels, Mister Bones seems to glitch and utters dialogue similar to that of HK-47.

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HK-47 is a well-loved figure in Legends lore, and the return of his class of droids is exciting for fans. However, the implications of the return are deadly. As The Mandalorian, "Chapter 13: The Jedi," shows, the HKs are more agile than any other droid, and the Magistrate acts safe in the presence of just one of them, alluding to their treacherous killing abilities. The original HK, HK-01, so strongly desired to end life that he started a droid revolution, unwilling to serve organics any further.

Diana Lee Inosanto as Morgan Elisabeth in The Mandalorian

Despite that setback, production on the line of assassin droids eventually continued with the HK-24s. This iteration was still few in number, as assassin droids proved to be unmarketable, but there were enough of them to be dangerous during the Days of Fear event in the Knights of the Old Republic comic by John Jackson Miller and Dustin Weaver. By this time, the HKs were highly adaptive, cunning and durable. Their sole weakness was their arrogance and sense of independence. Working together in a group was rare.

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The final iterations were seen during the Star Wars Galaxies card game, deadlier than ever with integrated blaster packages and sleeker designs, though their overall impact on Legends lore was slim. By this time, the appearance of an HK droid was meant to evoke both fondness and fear, their violent capabilities no longer in doubt.

Though Ahsoka Tano and Din Djarin dispatch the Magistrate's pair of HKs by the end of the episode without much trouble, that won't be doable for most individuals in the galaxy unlucky enough to meet one. If Moff Gideon or the Magistrate's secretive master have acquired more of these droids, it will be another horrific danger the struggling citizens of the New Republic have to face.

Created by Jon Favreau, The Mandalorian stars Pedro Pascal, Gina Carano, Carl Weathers and Giancarlo Esposito. New episodes arrive Fridays on Disney+.

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