Warning: The following contains SPOILERS for Young Justice season 4, episode 4,  "Involuntary."

The killer of Superboy in a recent episode of Young Justice season 4 might be the Time Trapper, a frequent foe of the Legion of Superheroes in the comics. The mystery assassin revealed nothing of his motivations, background or full capabilities during what little time he was on screen during the first four episodes of Young Justice: Phantoms. However, what little was revealed coupled with the mystery around the time-traveling killer is consistent with what has been confirmed and remained consistent regarding the Time Trapper.

The core plot of the first four episodes of Young Justice season 4 centered around the upcoming marriage of Superboy and Miss Martian. The two heroes had originally planned to travel to Mars to hold a traditional Martian wedding ceremony with Miss Martian's family but were quickly recruited by the Martian prince J'emm to investigate the murder of his father and the possibility that White Martian terrorists were responsible. At the same time, the heroes from Earth were being secretly observed by Saturn Girl, Chameleon Boy, and Phantom Girl of the Legion of Superheroes, a team of superpowered teenagers from the future who had traveled back in time 1000 years to prevent "one big thing" from happening. Precisely what the Legion of Superheroes was hoping to prevent was not explained, but the appearance of a blonde waitress resembling Saturn Girl in the Young Justice season 3 finale suggested that they had been watching Superboy and Miss Martian for at least a year before their journey to Mars.

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As the wedding day approached, it became clear that someone else from the future was hoping to thwart the Legion of Superheroes' mission. This unseen foe triggered a cavern collapse in the Young Justice season 4 episode "Needful," which almost revealed the presence of the Legion members to Miss Martian and Superboy. The same figure was seen for the first time in the Young Justice season 4 episode "Involuntary," where they set a chain of events into motion that seemingly brought about the death of Superboy.

What We Know About Superboy's Assailant In Young Justice

Young Justice Mystery Time Traveler in Involuntary

The mysterious assailant possessed advanced technology, including a spherical transport that allowed him to fly, become invisible and phase through solid matter. This device resembles the Time Spheres utilized by Rip Hunter, the Time Masters and the Legion of Superheroes to travel through time in the comics. Superboy's killer was also clearly clever and resourceful, having somehow acquired Kryptonite to set a trap for Superboy after his first attempt to expose the Legion of Superheroes failed. The assassin was also reluctant to reveal himself or attack his enemies directly. All of these clues, coupled with the presence of the Legion of Superheroes in Young Justice season 4, point to one classic villain from the comics: the Time Trapper.

Who Is The Time Trapper In The Legion of Superheroes Comics?

Legion of Superheroes Villain Time Trapper

First appearing in Adventure Comics #317 in February 1964, the Time Trapper was possibly the most powerful of the Legion of Superheroes' many enemies. Nothing is known of the Time Trapper's origins, though he claimed to have come from a future far beyond the 31st century of the Legion of Superheroes. This was apparently why he created a barrier, which he dubbed the Iron Curtain of Time, to prevent the Legion of Superheroes from traveling forward in time any further than 30 days along their own personal timelines, so they could not discover his history and prevent his rise to power.

Wherever he came from originally, the Time Trapper made his home in a citadel located at the end of time itself. It was from this paradox-proof fortress that the Time Trapper waged war on the Legion of Superheroes, for whom he harbored a special hatred. Yet the Time Trapper wandered the time stream and contested with other heroes, sometimes taking on new identities when facing particular foes. For instance, the Time Trapper disguised himself as a villain called the Time Master when fighting the Justice League of Earth-1.

Related: Young Justice: Everything That Happened Between Outsiders & Phantoms

Ironically, despite his hatred of the Legion of Superheroes, the Time Trapper was responsible for their creation in at least one reality. This was because the Time Trapper determined that the Legion of Superheroes were the only organization that could prevent the wizard Mordru of the Lords of Chaos from becoming powerful enough to one day kill the Time Trapper. This was revealed when the Legionnaire Valor successfully killed the Time Trapper and accidentally created the Mordruverse, a dark version of the 31st century where Mordru ruled all reality.

Much like the many variants of Kang the Conquerer in the MCU and Marvel Comics, the Time Trapper's true self has changed repeatedly over the years. The Time Trapper has been revealed, at various points, to be a corrupted member of the alien race known as the Controllers, the chaos sorceress Glorith, a time-displaced girl called Lori Morning (who might have been a younger version of Glorith), a corrupted future version of the Legionnaire Cosmic Boy, and the twisted Superboy Prime of Earth-0. These changes led Brainiac-5 to theorize that the Time Trapper might be either a "sentient alternate timeline" rebelling against the timeline of the Legion of Superheroes or the embodiment of entropy itself.

Theory: Young Justice's Mystery Fugitive Is (Or Will Be) The Time Trapper

Young Justice Mystery Time Traveler Close Up On Eyes in Involuntary

It can't be said for certain that the mysterious figure who arranged the death of Superboy in Young Justice season 4 is the Time Trapper, given how uncertain everything regarding the Time Trapper is. Despite his long history as an enemy of the Legion of Superheroes, it is unclear if the Time Trapper's ability to manipulate time is based on magic or science so advanced that it seems like magic, even by the standards of the 31st century. This would seemingly make it unlikely that the mysterious figure was the Time Trapper, given that their technology was comparable to what the Legion of Superheroes had utilized.

However, given that the Time Trapper was known to disguise himself as less advanced villains to hide his presence while fighting every superhero team across DC Comics' timeline, there is a chance that the rogue time traveler seen in Young Justice season 4 is a disguised Time Trapper. Another possibility is that Superboy's killer is a young version of the man who later became the Time Trapper. In either case, the time-traveling assassin's cleverness and ability to manipulate events around him while staying hidden are a far greater indicator that he's the Time Trapper than any costume or piece of technology.

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Young Justice season 4 releases new episodes every Thursday on HBO Max.