Flame Princess

Flame Princess is the princess of the Fire Kingdom, as well as Finn's girlfriend. When Jake asks Flambo if he knows any princesses Finn's age, he responds that he knows "Just the skirt... and she's way hot." Flame Princess is locked in a lantern in the main chamber of the Fire Kingdom when Jake first encounters her, where her father the Flame King put her; on the advice of Princess Bubblegum.

Personality and traits
Flame Princess has a volatile personality; she usually has a calm demeanor, though with rather frequent tendencies to sudden and violent mood swings. She is described as "passionate" by Finn, "evil" by the Flame King, and "intense" by Pendleton Ward. The Flame King also remarks that she is difficult to control. She seems to be very sensitive and quick to judge. She is also prone to unprovoked fits of aggression, as shown when she throws fireballs at her citizens just for whispering. Flame Princess is also impressionable in a positive way. She is very happy when Finn calls her beautiful. She was also interested when Jake was giving her gifts in the episode "Incendium" and excited when her dad let her date "Prince Finn," though this excitement quickly turns to anger when "Prince Finn" rejects her.

In the episode "Hot to the Touch," Flame Princess shows curiosity about her new surroundings by examining flowers. This sets them on fire and she seems a bit surprised by the reaction, indicating she doesn't know much about lands other than the Fire Kingdom. At the end of the same episode, she shows that she likes Finn, but thinks that they can't be together because they are opposite elementals, calling Finn "a Water Elemental" because of the tear that she felt from him.

In "Burning Low," she seems to be calmer and able to handle a part of her flame being doused. This is illustrated when Finn jumps into the water while his foot is on fire, but she doesn't visibly react. This was also shown in "Vault of Bones" when Finn tossed a lit torch in the water, she doesn't show any signs of pain even though it was her who lit it. That may be due to Finn and Flame Princess geting used to each other.

In "Vault of Bones," Flame Princess is shown to still have a desire to be destructive, even though she says she'll only destroy evil things.

Abilities
Being a fire elemental, Flame Princess is able to conjure up flames at will, transform other citizens of the Fire Kingdom into flambits, transform into a larger, more dangerous form composed purely of fire, hurl fireballs that can vary in size, and separate her body into distinctly separate groups of flames (shown when she ambushes Finn in "Hot to the Touch.") She appears to be able to consciously extinguish fire she has created; she does this when she notices Finn crying. She can also float and move very quickly, both of which leave a trail of flames.

Her weakness is water, shown after unintentionally setting off some of Princess Bubblegum's liquid pyrotechnics and when she puts her hand into a pond. The liquid pyrotechnics caused her to become unconscious, and touching the water in the pool caused her pain. The fires that Flame Princess makes are a part of her, and stomping on or dousing the fire hurts her, although in "Burning Low" Finn puts out a fire to his leg without harming her.

She is physically unstable. If her elemental matrix is exposed to extreme romance, she would burn through the Earth's crust and set off a series of reactions, causing a meltdown that would burn up the planet from the inside. This reaction was started when Finn kissed her in "Burning Low," but the crisis was averted. She can use her fingers to unleash small blasts of fire and throw disks of fire as seen in "Ignition Point."

She can emit a continuous flamethrower from her hands, but the length of time she can sustain it is debatable. She has a Scatter Fire ability, in which she emits four, manipulatible, bolts of fire. She can also make a Flame Sword, in which she concentrates an isolated flame, extending from her arm, that is intense enough to glow blue. Immediately following that, she used a Dash ability that sent massive pieces of shrapnel from a steel door (which she had just cleaved into four pieces) in all directions, as seen in "Vault of Bones." Also in the episode, she uses Heat Sense to sense that a tree is not made of wood. She does not leave a fire trail when she walks now, and she says she is a "42" (out of 100) at sending very weak, controlled bolts of fire. This indicates that she has gained considerable control over her abilities since "Burning Low," as seen in "Vault of Bones."

She has full manipulation of her body, morphing it into asymmetrical flames at will. Her father also has this ability, and it may be the norm among fire elementals.

Finn
Flame Princess does not actually meet Finn in person until the very end of "Incendium." After she is doused with Liquid Pyrotechnics, she unconsciously falls off the roof of the Tree Fort. Finn catches her as she is falling and brings her inside. She regains consciousness and angrily asks Finn why he doesn't like her; Finn replies that he does like her, which causes her to blush in surprise. Confused by Finn's apparent fickleness, she slaps him and warns him never to mess with her again—unaware that Jake was the original "Prince Finn."

In "Hot to the Touch," Finn wanders into the woods to search for the Princess, after asking Jake about her and saying he really likes her. When Finn finds Flame Princess he watches her from a bush at first, calling her innocent like "the steam off a puppy's nose searching for ham in the snow" and "a cute little flower." She touches a pool of water, hurting herself, and Finn jumps out from the bush to her aid. He then tells her that he was worried about her and thinks that she's beautiful. This causes her to glow, literally and figuratively, causing some fire to spread around Finn and herself. Finn puts out the fires in a panic which causes her pain, causing Flame Princess to believe that Finn is intentionally hurting her. She leaves in a huff without allowing Finn a chance to explain, not listening to his claims that he was not trying to hurt her.

After a brief chase, she concludes Finn is trying to impede her, so she decides to turn the Grass Lands into her own fire kingdom. She begins by heading for Goblin Kingdom to set it and its citizens on fire. Finn and Jake attempt to stop her with robo suits made by Neptr, but Finn only attempts to talk her out of it rather than put out her fires. When Finn realizes he cannot make her understand his feelings, he tears a hole in his robo suit and cries wishing he could "just like a girl." One of his tears falls onto the flames as she is walking away from him, causing her to turn around and witness him crying. She becomes convinced that he is a "Water Elemental," saying that all he does is cry and cry all the time. She comes to the conclusion that they are opposite elementals and that even if they like each other, they would hurt each other. However, Finn suggests that they try to make it work and that he can take it. She seems happy that he would want to defy nature for her, and both lean in to hug one another. As they hug, Finn gets burned and pushes her away. She looks at him appearing unsure, and then leaves saying, "Bye, Finn."

In "Burning Low," she and Finn are dating. Finn helps her build a new house in the Grass Lands out of wood scraps, and she tells him that she loves it. Her flames trail over to Finn's foot and he is surprised to realize that it doesn't hurt as bad as it used to; though, once the flames crawl up his leg he screams in pain and jumps into the water. Once he's out of the water, Finn and Flame Princess hug; although, Finn has to wear many layers of tinfoil to protect himself. While walking home, Finn asks Jake for advice about dating, to which Jake explains the concept of "tiers" and tells Finn that he should move on to Tier 2, which is kissing. Later in the episode, Finn goes on a date with Flame Princess (off-screen) and tells Jake that he wasn't able to kiss her yet (though he got 5 hugs), so he is still on Tier 1. Jake advises Finn to write a poem for Flame Princess in order to move things along. Finn tries to think about Flame Princess' qualities, and he ends up going outside and watching the sunrise, which gives him inspiration to write. He takes the finished poem over to Flame Princess' new house and reads it to her. After he's done they stare into each other's eyes and kiss. The kiss triggers a reaction and causes her to burn so hot that she melts through the ground. As she's falling, Finn grabs Jake's arm, ties it around himself and jumps down after her. Flame Princess' reaction is halted by lack of oxygen, and when Finn catches up to her she is extinguished and passed out. Though nearly out of oxygen himself, Finn picks her up and tells that he needs her to be okay. He then gives her artificial respiration, which causes her to re-ignite (though Finn passes out from lack of oxygen). Jake pulls them out of the hole and both of them are all right (parts of Finn's face are burned from the kiss). Finn picks up a rock and kisses it, then hands it to Flame Princess who kisses it as well.

In "King Worm," Flame Princess is feeding Finn (whom she calls "honey") soup; first lovingly, then angrily when he hesitates (he was confused, having been with Princess Bubblegum as her king and husband seconds earlier). However, Finn soon discovers that he is in a dream and she is not the real Flame Princess.

In "Ignition Point," Finn and Jake travel to the Fire Kingdom to retrieve Flame Princess' scented candles. While there, Finn finds out that Flame Princess is evil, but he seems pleased to know that she could possibly be turned to good.

In "Reign of Gunters," Finn takes the advice of a dating book called Mind Games and tries to act more mysterious.

In "Vault of Bones," she went to the Vault of Bones with Finn to prove to herself that she's good. After a giant Goo Skull captures Finn, she rescues him and calls him her boyfriend for the first time. At first, Finn thought he was going to be burned alive because of how Flame Princess approached the Goo Skull, but after he's rescued, Flame Princess says she would never hurt her boyfriend.

Jake
Jake enters the Fire Kingdom to court Flame Princess on behalf of Finn, who is feeling heartbroken after having been pushed away by his previous love interest, Princess Bubblegum.

Jake sings her a song and accidentally kills her father's jester by spilling water on him, both of which she apparently enjoyed; however, she does not react much when Prince Finn kills Jake.

In "Burning Low." Jake does not interact much with Flame Princess but they seem to be friends and Jake has approved of her; he even helps Finn in courting her with a poem.

In "Ignition Point," they interact much more and they seem to be comfortable with each other; it was Jake who suggested going to the Fire Kingdom to get her the scented candles.

Jake seems glad to see Finn happy with Flame Princess, as he was the one to seek her after Finn was rejected by Princess Bubblegum. Jake also keeps his distance when Finn and Flame Princess are together, as shown in "Burning Low" when Finn asks Jake if he wants to check out Flame Princess' new house and he politely refuses and tells them to go ahead. Also in "Vault of Bones," while Flame Princess and Finn are playing cards, Jake offers them chamomile tea to show his support of their relationship.

Princess Bubblegum
There has not yet been any direct contact between Flame Princess and Princess Bubblegum in the series, but in "All the Little People," little Flame Princess and little Princess Bubblegum fought over little Finn. She also revealed to Jake in "Burning Low" that Flame Princess is unaware that she was the one who had the Flame King lock up his daughter in the lantern due to her physical instability. Princess Bubblegum knows, in great detail, about Flame Princess's elemental matrix, what "extreme romance" would do to it, and how to stop the resulting reaction. Also in "Burning Low", Princess Bubblegum had been accused of being jealous of Finn and Flame Princesses relationship. Throughout the episode she denyed this, saying she was only worried about Flame Princesses instabililty and the sake of ooo. At the very end of the episode, she is seen staring at Finn and Flame Princess and saying,"Oh Finn." Jake sees this and give her a smirk, and in response she says,"What?". He replies, "Jealous?" to which she says,"Shut up."

Flame King
Her father, the Flame King, understands his own daughter as "evil," having said so during "Incendium" even in introducing her to "Finn" (Jake molding part of his body into a Finn-shape) when they first meet. In "Ignition Point" Flame Princess admits to hating that her father locked her away in the lantern for all these years and thus refuses to go back to Fire Kingdom after she finally leaves it behind when meeting Finn.

However, Flame King's concept of his daughter being evil is merely a factor of all Fire Kingdom citizens being evil and traitorous to one another, with him believing her like others yet with physical instability that would cause harm to anyone around her. He slightly could believe his daughter could gain a "good" alignment if she hung around people like Finn, but he doesn't know if it could work due to Flame Princess' fiery nature.

He later attempts to send subliminal messages to her while she sleeps by saying "evil," but it quickly stops when Flame Princess wakes up and sees this, leaving her shocked. He does so again at the start of "Vault of Bones" but stops upon realizing that she's not alone, causing Finn to look for a way to counteract his influence.

Ice King
There has not been any direct contact between Flame Princess and the Ice King, though it seems that he knows her since he mentioned Flame Princess in "I Remember You," probably from hearing about her from Finn and Jake. Flame Princess is one of the princesses that the Ice King calls okay. It is unknown if Ice King has captured Flame Princess before, but if he did it would be very hard because she could melt her way out of all his traps.

Appearance
Flame Princess has long orange-red hair that is like fire and as such flows above her head. Her skin is yellow-orange and she usually wears a long, sleeveless dress that touches the ground. At first, she doesn't wear shoes, though her dress usually hides her feet from view. She has two diamond-shaped, red gems; one on her forehead and the other on the front of her dress. The red gem on her dress is shown to be a part of her dress and not her exemplified when Flame Princess had a different outfit on in "Ignition Point." She has black eyes that sparkle white and yellow in the light of her fire. Her arms are also portrayed as thicker than the majority of characters.

When her flames are doused, her skin changes to a pinkish-gray hue, and her hair falls down her back and becomes a dull shade of maroon. Once in dry conditions, she returns to her normal appearance quickly. When Flame Princess is deprived of oxygen she turns a light shade of blue, as seen in "Burning Low."

She is normally seen wearing a red and orange dress with a gem in the middle that matches the gem on her forehead and her hair is seen up. In "Ignition Point" she is shown with her hair in two side-buns and she begins to wear shoes. The animatic also showed her wearing a choker, which was later removed. In "Vault of Bones" she has a strapless dress and her hair appears to be shorter than usually seen.

Quotes
See Flame Princess/Quotes

Major appearances

 * "Incendium"
 * "Hot to the Touch"
 * "Burning Low"
 * "Ignition Point"
 * "Vault of Bones"

Minor appearances

 * "King Worm"
 * "All the Little People"

Mentioned

 * "Reign of Gunters"
 * "I Remember You"
 * "Puhoy"

Comic

 * Issue 2 (Mentioned)
 * Issue 4 (Non-speaking Cameo)
 * Issue 7 (Non-speaking Cameo)

Trivia

 * Pendleton Ward and the show's cast first introduced Flame Princess at Comic-Con 2011.
 * Natasha Allegri has drawn Flame Prince, a gender-swapped version of Flame Princess, in her artwork, but he has yet to appear on the show. He has, however appeared in the mini comic that started in early January.
 * Flame Princess is the only known princess to have invaded another kingdom by herself.
 * In the original storyboard for "Hot to the Touch," Flame Princess was supposed to kiss Finn; however, the idea was dropped and reused for "Burning Low."
 * When Flame Princess transforms into her larger form, her face resembles that of her father, the Flame King.
 * She wears a different outfit and begins wearing footwear in "Ignition Point."
 * Also, she wears another outfit with no footwear in "Vault of Bones."
 * Although it appears as if Flame Princess' hair is made of fire, it does not disappear when she is extinguished or wet; instead it falls down to her back and behaves like normal hair.
 * She is different than the other flame people curiously, being that she can be completely wet and yet only be rendered unconscious at the most, instead of killed. She is one of the few flame people with a humanoid shaped body and she is apparently the only one with a human-like physical body (an example is her skin and hair behave like a humans) rather than one composed only of fire.
 * When in a doused state, her gems appear to turn a maroon color.
 * Flame Princess will be starring in a new Adventure Time Original Graphic Novel, where she embarks on her first adventures with Finn & Jake
 * There is a Pet Society costume of Flame Princess.
 * She refers to Finn as her Boyfriend in "Vault of Bones"
 * She is one of the two princesses who have run away from home and lived out in the grasslands because they hated their parents and how they treated them. The other one is Lumpy Space Princess.
 * She is one of the two known princesses who have a gem on their foreheads instead of wearing a crown. The other one is Lumpy Space Princess.
 * Finn refers to Flame Princess as his Girlfriend in "Puhoy".