The Lich (formerly named the Lich King in the original pitch and "His Hero," and referred to as Sweet Pig Trunks in his baby form, or just Sweet P for short) is a powerful undead being and a major antagonist in Adventure Time.
In "The Comet," it is revealed by the Purple Comet that the Lich, like Finn, started out as an incarnation of the Catalyst Comet. The Purple Comet explains that it has embodied both the ultimate good by once becoming what would later be Finn, and the ultimate evil by at some point becoming the Lich in their respective time periods.
His first episodic appearance is in "His Hero" where the hero Billy casts him down. He was imprisoned in the ancient tree in the Candy Kingdom, but escapes and plays a significant role in "Mortal Folly," "Mortal Recoil," "Jake the Dog," and "Finn the Human." The Lich goes on to kill Prismo and releases the criminals in the Crystal Citadel in "Wake Up" and "Escape from the Citadel." However, by the end of the latter episode, the Lich is turned into a harmless baby by the Citadel Guardian's healing blood, and is adopted by Tree Trunks and Mr. Pig and renamed "Sweet Pig Trunks," Sweet P for short.
In "Gold Stars," it is revealed that the Lich's evil is still contained within Sweet P, and can take over when Sweet P is threatened and emotionally charged. Sweet P does not realize the evil lurking inside him, attributing his blackouts and dreams of being the Lich to being 'just a dream.'
Sweet P also possesses the potential to use the Lich's powers as indicated when he shows his victims another dimension, although it seems to be more limited as the Lich's death breath does not kill its victims as it had done before with Prismo.
As the Lich Edit
Before his change, the Lich wore a helm with curled horns, one of which has broken off. However, before being struck down by Billy, both of his horns were intact, so it is possible that it got broken off around that time. He also had intact horns in Princess Bubblegum's vision. The Lich also dresses in a large, loose robe with multiple layers and a large cape that that is severely torn at its end.
Physically, the Lich is also remarkably large. In the flashback in "His Hero," the Lich is shown to rival Billy in size. The arms of the Lich are bare bones with various decayed tissues, and his skeletal hands burn with an eerie fire when casting spells. His face is defined by horrific green lights as pupils peering out of his empty eye sockets, and pale undead skin is pulled tight against his nose-less skull. His skin is frayed away from his lips revealing a wicked and perpetual grin.
As Sweet P Edit
After being splashed with the Citadel Guardian's healing blood, the Lich grew fresh organs and skin, causing him to take the form of a giant baby with almost no recollection of his previous form. As Sweet P, he is still very large, towering over most other characters. While he still has his horns, they're covered with his new skin. As shown during his transformation from his Lich form, Sweet P has green eyes.
After being adopted by Tree Trunks and Mr. Pig, he had received multiple new outfits of clothing. In "Jake the Brick," he wears one pieced footed blue pajamas with red polka dots. In "Gold Stars," he has an apple-green shirt with a red apple on the front, with matching shoes, shorts, and a matching hat, all knitted by Tree Trunks, although the shirt seemed to be too small as it exposed his stomach. In "Be Sweet" Sweet P wears different pajamas, this one being two pieced, and light blue and striped.
Aside from his immortality, the Lich has a medley of unholy powers. The most commonly used is his ability to summon green flame-like energy around his hands and fire it at his opponents. Also, while possessing Princess Bubblegum, he demonstrates pyrokinesis when he sets her room on fire with his mind.
The Lich also seems to exude an aura of death and rot around him. Whether this is done consciously is unknown, but living creatures and objects have been seen to rot and die as they come in contact with him or his general presence. This is shown when trees died as the Lich passed through a forest, and when he crossed Iceberg Lake, fish died in his path. In addition, the Lich can breath a black, lethal gas as seen in "Escape from the Citadel" when he kills Prismo.
In addition to his deadly magic, it was revealed that the Lich has the power to control people's minds, either through telepathy or spoken commands. The Lich's influence was so great that he posed a threat to anyone nearby, even while he was still trapped in the Candy Castle. Moreover, he has the ability to possess other people, as seen when he possessed Princess Bubblegum. The Lich is also able to utilize necromancy, as seen when he controls the corpses in his lair to attack Finn and Jake.
The Lich also possesses great physical abilities as he was able to quickly dodge Finn's energy attack with Billy's gauntlet. Later, he easily caught Finn's punch bare handed and shattered the gauntlet into pieces. In addition, the Lich is also very mobile as he possess the ability to fly.
The Lich sustains his massive strength by drinking from his Well of Power, a noxious, magic pool of glowing green liquid located in the depths of his lair. After he had possessed Princess Bubblegum, he substituted his original well with a mixture of toxic chemicals such as gasoline, lighter fluid, bleach, and plutonium that he (appearing as the Princess) ordered Finn to retrieve.
While his power is truly a force to be reckoned with, the Lich has a few known vulnerabilities. His main weakness is the Gauntlet of the Hero, a magical weapon previously owned by Billy that fires intense energy blasts. This weakness is now moot as the Lich destroyed the gauntlet with ease when he grabbed Finn's arm and caused the gauntlet to disintegrate. Another item able to work against the Lich is the sweater Princess Bubblegum gave to Finn. Imbued with the power of "liking someone a lot," the sweater protected Finn from the Lich's flames and was later used as a weapon. With it, Finn was able to attack the Lich by assaulting his head and eyes with the sweater, causing his body collapse into dust and force his essence to have to find a new host. However, the sweater does not seem to affect the Lich when he is possessing Princess Bubblegum. The Lich is also unable to control a person's mind if he/she is wearing a certain type of magical jewelry. While generally impervious to physical attack, traditional methods may have some limited effect on the Lich, as seen in the flashback where Billy cast him down with a kick to the face.
The Lich is driven by a rather single-minded goal: to destroy all life. He appears to show little interest in anything that does not further his ambitions towards this dark end. He also has an apparent hatred for all living things, as Princess Bubblegum said that his only desire was to destroy life, and his wish to Prismo was "for the extinction of all life." It has been said that he brings sadness everywhere he goes.
He is viciously cunning and quick to learn from his mistakes. He methodically targets people and things that have proven a problem for him in the past by either destroying them outright such as in the case of the Gauntlet of the Hero or using them as pawns to further his own agenda in the case of Billy to manipulate Finn. As shown in "The Lich," he is highly skilled at deception, as he was able to fool Finn and Jake into helping him while disguised as Billy. At the end of the episode, he tauntingly thanks Finn for opening the portal for him. He is a quick thinker, pretending to be horrified when Finn tried to smash the Enchiridion, even though that would cause the portal to open.
The Lich is rather taciturn and speaks only in brief statements. Because he seldom speaks, his words carry great gravity. An example would be when the Lich calls Ice King "a weak fool." This could be because nearly anyone that came near him wore a protective gem in "Mortal Folly" and was weakened in "Mortal Recoil." In the episode "The Lich," he was able to talk freely with Finn and Jake. In spite of his intractability, he is visibly shocked when Finn survives his fire attack, and he laughs heartily when Finn attacks him with the sweater provided by Princess Bubblegum. He was also visibly confused when Jake altered his wish. He has only raised his voice once, when Finn asked the possessed Princess Bubblegum if everything was all right.
The Lich's most notable flaw is his arrogance and his single-minded nature. In each case his defeat has been at the hands of opponents towards whom he was derisively dismissive. He laughed at Finn's attempts to stop him and shrugged off the Ice King as a fool yet it was through the combined efforts of these two individuals that he was dealt a crushing defeat and forced to possess the body of a lowly snail to escape at the end of "Mortal Recoil." After regaining his strength the Lich manipulates Finn into opening a portal into the heart of the multiverse. Once again he falls prey to his arrogant and single-minded nature when he ignores Jake grabbing onto him with a dismissive grunt and continues onward towards his final goal rather than dealing with the two stow away heroes he is dragging into the portal with him. This oversight later proves to be the undoing of his masterful plan, leaving him stranded in Prismo's time room with his one wish already spent thanks to the two meddling heroes and some friendly help from Prismo.
After turning into a humanoid in "Escape From the Citadel," he loses his old personality and gains a new, infantile one. He seems harmless and does what most infants do, such as playing with toys. In addition, he is kinder and tries to be more considerate of others. As of "Gold Stars," the Lich is still revealed to be trapped inside of Sweet P and Sweet P is almost his own person now.
Story in "Adventure Time" Edit
Although the exact origin of the Lich is ambiguous, it is likely that he was the result of detonating the Mushroom Bomb (one of the last weapons dropped during the Mushroom War and the likely cause of the unnatural creatures of Ooo, such as Candy People, Sign Zombies, etc). When Finn wishes that the Lich never existed, he prevents the Mushroom Bomb from ever going off, thus creating the Farmworld alternate dimension. In the Farmworld dimension, Simon Petrikov (previous form of The Ice King) prevents the Mushroom Bomb from going off, sacrificing himself in the process and sending the world into a 400 year long Ice Age. After this Ice Age, life continued un-mutated for approximately 600 years, and characters such as Farmworld Finn were created.
The suggestion that the Lich is more of a mutation rather than a magical being is further supported in "Jake the Dog." When Farmworld Marceline and Farmworld Jake fell into the Lich's well, Marceline became a skeleton and Jake transformed into a version of the Lich itself. So the Lich's body was likely created when someone or something made contact with the Lich's well, but it also means it turns the host's abilities into his own. So this is why Farmworld Jake only attacked Farmworld Finn with its bare hands, not with magic spells or anything else, with the same applying to Billy. It is unknown if the Lich's body seen in "Mortal Folly" was his original body, or one he stole.
However, due to Prismo's statement that Lich-possessed Billy was "a ghost wearing a dead guy," coupled with the fact that Farmworld Jake was transformed into a Lich-like monster when mutated, it is possible that only the Lich's former body was created by the Mushroom War and was possessed by the Lich, who had existed before. This is backed up by the fact that the Lich survived his destruction at the hands of Finn as a ghost (which then possessed Princess Bubblegum, the snail, and eventually Billy). From this, it can be said that his overall powers and abilities may differ based on what he uses as a host, but this remains to be clarified.
The episode "Evergreen" suggests that The Lich may have originally been the comet of that time in some shape or form, judging by its greenish glow and "horns," as well as Evergreen's statement of the comet apparently wanting nothing else than to destroy all life on the planet. This may suggest that the mushroom bomb simply gave him a physical body or a consciousness rather than outright created him. (Note: in the episode "The Comet" It is confirmed by the purple comet that the Lich was once the catalyst comet.)
Based on the episode "Gold Stars," it is also possible that the Lich's origin goes back to when the universe didn't exist yet, being himself one of the primordial monsters he describes in his speech. Also, in "The Comet" it is implied that the Lich was indeed connected to the Catalyst Comet (presumably the green one seen in "Evergreen"). However, the exact means of how he came from the comet is unknown, although it might have just been a past life of his as it was for Finn.