The following contains spoilers for episode 5 of Loki on Disney Plus.
For the Loki episode "Journey Into Mystery," most fans were probably focused on the many variants of the title character appearing in the episode. They, however, weren't the only comic book-inspired characters to land on the show. The fifth episode also featured the introduction of Alioth. Alioth might conjure up memories of the Smoke Monster from ABC's drama LOST, but he made his comic book debut in 1993.
While it's hard to pin a temporal cloud as a villain, Alioth likely qualifies in both the comics and in the Loki series. The show describes him as a kind of guard, but in the comics, he's got a connection to a different villain who is also associated with time. In fact, that very villain will be joining the Marvel Cinematic Universe.
Alioth In Loki
When Ravonna Renslayer prunes Loki in episode 4, that pruning doesn't kill him. Instead, as the next episode reveals, all pruned variants and timelines end up in The Void. The Void is the space at the end of time where nothing else can move forward. At least, that's how Renslayer explains it. The Void is also home to Alioth. It appears that the reason nothing moves forward is really Alioth himself.
Alioth, appearing as a giant storm cloud, has dominion over The Void. Though there are many Loki variants surviving there, they're doing it underground. Alioth consumes everything on the surface. The audience sees the cloud absorb people, vehicles, and buildings in the few glimpses offered.
Sylvie theorizes that Alioth isn't just the monster of The Void though. She believes he's guarding the way to the real Timekeepers. The reason no one can find them - or whoever created the Time Keepers - is because Alioth consumes them rather than let them through The Void. Her theory may very well be true since her attempt to enchant Alioth and access the storm's memories leads her and Loki to view a castle-like fortress through the cloud. Beyond that, little is known about the entity in the MCU so far.
Alioth In Marvel Comics
Alioth first appeared in a 1993 comic called Avengers: The Terminatrix Objective. Like a lot of the concepts pulled from the comics for Loki, he was created by writer Mark Gruenwald (and artist Mike Gustovich). The four-issue limited series sees the Avengers battling a villain who can travel to the far reaches of time. Alioth isn't their primary villain, but the character is an interesting one.
According to the limited series, Alioth is the first being in Marvel history to break free from time completely. Being essentially a sentient time storm likely helped with not being constrained to one timeline. It's said that Alioth's birth occurred at the same time as life began on Earth. Alioth's actual abilities are very similar to what's shown in the Disney Plus series.
The nebulous creature can exist across all timelines and realities. In fact, when it consumes matter in its path, it only grows. It also stretches to consume realities adjacent to the one it's already consuming, making it nearly impossible to stop. Alioth is also capable of completely negating "temporal energy" so time travelers can't just go through Alioth. Whether or not that same skill will apply in Loki remains to be seen as Sylvie intends to travel through Alioth to find the real Timekeepers.
Since Alioth does seem to be incredibly similar to its comic book counterpart, it stands to reason that the creature might have the same time traveling rival in the MCU that it does in the comics. That rival is Kang the Conqueror.
Alioth Hints That Kang Is On The Way
Loki hasn't been shy with its hints to Kang. Ravonna Renslayer is the love of Kang's (very long) life. An Easter egg in episode five hinted at the existence of his company, Qeng Enterprises, existing in a branched timeline. Kang, however, isn't officially confirmed to enter the MCU until Ant-Man and the Wasp: Quantummania. While plenty of fans believed Loki would, like WandaVision, be responsible for setting up Doctor Strange In The Multiverse of Madness, that might not be the case. It looks more and more like Loki is setting up for Kang's big MCU debut.
When Kang begins to conquer the universe, variations of himself across timelines do it. His kingdom doesn't just exist across countries, but across timelines. There are, however, certain periods of history Kang doesn't inhabit because he doesn't want to come up against Alioth - though he likely wouldn't admit to being intimidated. Alioth actually "conquers" more timelines than Kang, but he does it by devouring them instead of ruling them.
During Avengers: The Terminatrix Objective, Kang is actually out of commission. Instead, it's Ravonna Renslayer with the codename of Terminatrix who calls the shots on his behalf. It's also Ravonna who accidentally frees Alioth from the barrier Kang created to keep the other entity out of his empire. Alioth then sets his sights on consuming everything, and yet another temporal being, Tempus, was used to stop that. The complicated storyline likely won't play out in Loki, but it will certainly be interesting to see what the episode 6 finale does borrow from the comics where Alioth is concerned.