The Lich (Adventure Time)

"Fall.....You are alone, child. There is only darkness for you, and only death for your people. These ancients are only the beginning. I will command a great and terrible army, we will sail to a billion worlds, we will sail until every light has been extinguished. You are strong child but, I am beyond strength. I am the end. And I have come for you, Finn."

- The Lich

The Lich, also known as the Lich King, is a major villain in Adventure Time. After being defeated in "Mortal Recoil", the Lich apparently continued to inhabit the body of the waving Snail, which appears in every episode. In the episode "The Lich", he posed as Billy to force Finn to assist him to unlock the true secret of the Enchiridion, and in the episodes "Wake Up" and "Escape From The Citadel", he pursued Finn to the Citadel before his presumably he was transformed by the blood of the Guardians of the Citadel into a human child and put by the door steps of Mr. Pig and Tree Trunks and he is renamed Sweet Pig Trunks (Sweet P) by his now adoptive parents.

As of "Gold Stars" it is revealed Sweet P has frequent Nightmares of the Lich and the Lich can temporarily possess Sweet P when he is in extreme danger, or if he sees a fire.

History
Early on, the Lich (or Lich King) has a plan to suck all life from the Land of Ooo, the setting of Adventure Time. Using the stolen power, he plans to destroy all life, but he was attacked by the hero Billy. He was trapped in a prison of amber in the heart of the Candy Kingdom after Billy personally pounded him into it.

Biography
One day, in the Candy Kingdom, Princess Bubblegum, the ruler of the Candy Kingdom, Finn the Human Boy, and Jake the Dog were thinking hard. While Finn and Jake were dreaming about regular day dreams, Princess Bubblegum saw a hellish scene where a threatening black shadow stands in front of of a backdrop of flames. Fearing that the amber prison was weakening, she takes Finn and Jake with herself to the prison. They wear protective gems first so they do not fall prey to the Lich's mind-controlling voice, which was still a problem even though the Lich himself wasn't.

While they were up there, the Waving Snail (an Easter Egg which appears in every episode) comes out of Finn's backpack. Since the Snail was not wearing a gem, its eyes go big, hollow, and black with a strange glow coming from them. Slowly, Waving Snail moved to the sphere of amber. The Snail breaks the prison and an oily liquid comes out and forms the Lich, which turns into a black vapor and runs away, leaving behind a black trail of death.

Princess Bubblegum gives Finn the Gauntlet of Billy, which defeated the Lich the first time, and they start to chase the Lich. But Ice King comes in and pesters Finn and Jake for permission to marry Princess Bubblegum. Finn and Jake shut him out and run along where they come close to hit the Lich with a power beam from the Gauntlet several times but Ice King gets in the way.

Annoyed, Ice King decides to kidnap Princess Bubblegum instead. Just as the Lich is about to be blasted, Ice King comes in with the captive princess. This allows the Lich to escape to his Lair to regain his power via the Well of Power.

Following the Lich into the Lair, Finn and Jake are met by dead human skeletons which attack them, but are destroyed by the Gauntlet. Going down even farther, they look through a collapsed ceiling the Lich standing over the Well of Power (a radioactive pit of broiling green liquid). The Lich thrusts his hands into the Well and soaks up the power making pale green smoke come from the Lich's eye sockets.

Finn then fires a beam down at the Lich and Jake uses his stretching powers to make wings that glide Finn towards him. Before Finn could deliver another blast, the Lich grabs Finn by the Gauntlet and brings him up to his huge skull face. The Lich brings up a finger to its mouth and says shhhhh. The Gauntlet then explodes in thousand of pieces leaving Finn`s hand singed and then the Lich throws Finn to the other side of the room.

Ice King and Princess Bubblegum come in, see the Lich and freak out. Jake then goes up to the Lich carrying Finn on his back and barks at him. The Lich then simply creates a ball of burning green fire that hits Jake in the face, sending him teetering backwards. Finn hits the floor and shatters his protective gem and his world goes dark.

First Defeat
The Lich tries to make Finn walk into the Well of Power, but Finn fights the heavy voice of the Lich King. He goes back into his world and Finn brings out the sweater that Princess Bubblegum had made him and uses that as his weapon.

Finn pulls the sweater in one eye socket and then out the other and starts to pull. Surprised, he staggers but then regains balance and laughs at Finn. The hero breaks the Lich's skull and he turns to dust, sending him to the floor.

Jake then helps Finn up and the Ice King frees Princess Bubblegum. With that the ice wizard drops Princess Bubblegum into the broiling Well of Power.

Possessed Bubblegum
Later what remains of Princess Bubblegum is brought to a hospital where she is revived. But she seems strange. In her room she tells Finn to bring her some things. At that moment Jake comes in with Peppermint Butler but when Peppermint Butler sees Bubblegum talking to Finn, he goes on four legs and hisses at the Princess and scampers off.

When Finn leaves to get the 'things' for the Princess Jake tries to sing her a song but she is angered by this and twitches followed by yelling at Jake in an angry babble. Jake again tries to play a song and she put her hand into the large amount of picked flowers brought to her by Finn and Jake and they all wilt and die. Again Jake tries to sing and Bubblegum and her bed fly into the air and all of flowers are consumed by a fire that has the faces of a thousand of tortured spirits.

Jake runs out and tries to warn Finn that something is wrong and tries to prevent him from giving Bubblegum the 'things' she wanted. These things where bleach, gasoline, etc. but before Jake could finish Bubblegum takes all of the things from Finn. They enter her room and find Princess drinking the mixture of the toxic things that Finn had gotten.

Mutated Princess Bubblegum grown into a huge black demon which punches Finn and Jake through a wall and hurtle them beside the Ice King who was listening through the wall with a cup. The Princess grows even bigger until she break through the ceiling sending out chunks that almost kill several candy citizens.

Second Defeat
While in the mutated demon body the Lich runs to the gates of the Candy Kingdom and is fought by a giant Gumball Guardian who is easily smashed to bits. Finn and Jake go out to fight her but Finn is punched taking out some of his teeth he is sent back to the tower where he came from; Jake is then caught by the Lich and is strangled.

Finn and Ice King work together and Finn stalls the demon while Ice King freezes it and the plan works. But then Bubblegum's foot was frozen  at a wrong angle and the ice covered Princess fell over and broke into shards.

Return
A close up shot at the end of Mortal Recoil shows Waving Snail on a window ledge waving forcibly. Its eyes were sunken and dark and filled with a green deadlight which showed that it was a host body for the Lich King who was angry and looking for revenge on Finn. It is likely that since he is a lich he would have a Phylactery, which would house his soul.

Possessed Waving Snail
The Snail is used by the Lich in "Mortal Folly" to free the Lich from his amber prison. The Lich does so by taking control of Snail's mind and making him/her/it break open the prison. After the events of "Mortal Recoil", the Lich returns to the Snail's body. As of season 3, the Snail has continued to appear in every episode, now in possessed form. In "Following In Your Footsteps" the bear gives the possessed snail the hero's Enchiridon. In "The Lich," the Lich ends up changing bodies moving to that of the deceased Billy. After this, the snail no longer shows any further sign of possession as revealed in "Up a Tree."

Possessed Billy
The Lich possesses Billy in most of the episode "The Lich," and tricks Finn and jake into gathering the gems of power needed to activate the Enciridion. The events surrounding how the Lich assumed Billy's identity remained ambiguous until the Season 5 season premiere where it was shockingly revealed by Prismo that the Lich was in fact wearing Billy's dead body as a macabre disguise the entire time when he refers to the Lich as, "a ghost wearing a dead guy".

Possessed Farmworld Jake
Finn used his wish to wish that the Lich never existed. This however triggered a series of events that ended with Farmworld Jake coming in contact with the pool of green goo created by the Mushroom Bomb, mutating into a Lich/Dog hybrid and attacking Finn.

Imprisonment
After seeing how horrible life was with the Lich never existing, Jake tries to save the day with his wish. Prismo tries to help him with the perfect wish and Jake ends up wishing to change the Lich's wish to sending him and Finn home. Jake and Finn go back in time and sees the Lich get ready to wish for the end of all life on Ooo. However, thanks to Jake's wish, the Lich ends up wishing for Finn and Jake to go home safely. Realizing what he said, a now surprised Lich tries to change his wish but it was too late and Finn and Jake go back to Ooo, with the Lich now stuck in the Time Room, his wish wasted. Finn is concerned with the Lich's wish but Jake assures him that everything is now fine.

Release
Some time after the events of Billy and the Time Room, Finn learns of a place called The Citadel, where his father has been imprisoned. The Lich is currently in a standstill, with no one to kill and lying lifeless in the Time Room. Finn tries to get the the Citadel by taking Prismo's human body, in which killing him will commit a cosmic crime and take Finn and Jake  to the Citadel. However, with a new presence in the room, the Lich springs to life and knocks Finn and Jake aside, killing Prismo and destroying his human body. A portal opens and the Lich laughs, before being crystallized and drawn into the portal.

The Citadel
Finn and Jake grab on to the Lich's crystallized form, and it is drawn to a sphere in the middle of the Citadel alongside countless other villainous creatures. As Finn and Jake search for Finn's dad, the Lich's breath corrupts the crystal and releases a noxious gas throughout the citadel, lighting a black fire and melting the crystals imprisoning the creatures within. After Finn and Jake reunite with his father (who does not recognize Finn) the Lich appears in the water and the crystal containing him explodes, reducing him to a skeleton.

Third Defeat
The Lich, as a skeleton, knocks out Jake and Finn, and slowly walks towards them. He proclaims that he will use the Citadel's denizens as an army and extinguish all light and life. He reaches out his hand to Finn to kill him, but Finn sprays the Lich's hand with a Guardian's blood, causing flesh to grow on the Lich. In pain, the Lich starts uttering nonsense, and Finn, realizing this weakness, sprays Lich with the blood, causing him to grotesquely mutate and collapse. When Finn returns to Jake after failing to reach his father, Jake reveals the Lich reborn as a human child, and it is though that his mind is rebooted. At the end of the episode, "Baby Lich" says a proud "Hello!"

An Evil Lurking Within
However even turning into a baby wasn't the last we have seen of the Lich In the episode "Gold Stars" his human child form, Sweet Pig Trunks (Sweet P) has a nightmare about his past life as the Lich as he appeared in "Mortal Folly" laughing and destroying everything. It can be implied that he has frequent nightmares. When the King of Ooo and Toronto threaten to burn down the orchard, the Lich regains control over Sweet P and almost kills them. With this said, it is revealed the Lich is still alive, but just trapped inside Sweet P's subconscious and awakens when he sees fires, or is threatened.

Adventure Time Comics
The Lich returns again as the main villain in the first 3 issues. In the first issue, it escapes the Waving Snail by journeying into The Bag of Holding, an ancient artifact capable of sucking up the entire world. The Waving Snail returns to its original form and the Lich to its skeletal form seen in "Mortal Folly." The Lich seeks revenge on Finn and Jake and the Land of Ooo by sucking people in the magical Bag of Holding, which contains mostly sand and Desert Princess, a sand-controlling fusion of various Candy People sucked into the bag on a previous occasion. The Lich's goal was to suck all of Ooo into the bag and throw it into the sun, but Finn and Jake, with the help of Desert Princess, Princess Bubblegum, Marceline, Lumpy Space Princess and an army of Finn and Jake clones made from ice and desert sand, tear a hole in the bag and assault the Lich with physical blows and "battle burn" insults until the bag is destroyed and the Lich is hurled into the sun. The sand from the bag is later used by Desert Princess to fill in the hole in the planet made from the Mushroom War.

As stated above, this story is likely not canon to the TV series' continuity.

Quotes
''Sssshhhh... ''

''Aren't you cold, Finn? ''

''Walk into the well, Finn... ''

''You are a joke to me! ''

''The book, Finn. Give me the book. ''

''Thanks, Finn. I couldn't have done it without you.''

Wake up.

Fall.

You are strong child, but I am beyond strength.

Stop.

Here's your Gold Star!

Trivia

 * The Lich is the most evil villain in Adventure Time and is most likely the true main antagonist of the entire series.
 * He is also considered one of the most evil and serious Cartoon Network villains as well.
 * The Lich is voiced by Ron Perlman, who also voiced Slade from Teen Titans.
 * The Lich is still referred to by his old name, Lich King, in various official episode summaries and clip descriptions on Cartoon Network's site, indicating that the name change may have been done very late in production.
 * The original name, Lich King, was only changed because this name already belonged to a World Of Warcraft character, and Frederator Studios was afraid that they would be sued.
 * In fantasy fiction, a lich is a powerful magician who has transformed himself into an undead creature to achieve immortality.
 * The Lich is the first character Finn and Jake have faced that has endangered the fate of the world.
 * The Lich was redesigned at least once, as the creators felt that his original design wasn't scary enough.
 * The Lich's final design is similar to that of The Horned King from the Disney film The Black Cauldron, which is an adaptation of the novel The Book of Three.
 * On CartoonNetwork.com, you can set your profile picture as the original Lich.
 * In "King Worm," he makes his second normal body. He is also seen, as the snail, at the end of the episode behind Finn after defeating King Worm.
 * In "The Lich" he makes his third appearence in his normal body in Finn's premonition dream.
 * In the episode "Gold Stars" he makes his fourth appearance in his regular body in Sweet P's nightmare.
 * In France/Belgium, there was a translation problem with Lich King's name. During his appearance in "His Hero," he is called " Le Roi sangsue," which translates to "Leech King."
 * In the original storyboard of the Lich episode, Billy/the Lich explains he would push the Lich into the Crystal Citadel, a prison that no one can escape from, one of the prisoners being Finn's father.
 * When Billy/the Lich tells Finn about his real dad, Finn does not know he was adopted, even though he has the memory of Joshua and Margaret taking him from the woods.
 * The Lich was originally supposed to convince Finn to give him the Enchiridon by bringing back his parents.