Lady Rainicorn

Lady Rainicorn is a unicorn-rainbow hybrid. She is Princess Bubblegum's pet and companion. She is also Jake's girlfriend, and sometimes follows Finn and Jake on their adventures. She speaks only Korean, using English only when equipped with a Universal Translator. Jake is the only other being in the Land of Ooo, besides Lady's parents, that is shown to understand Korean, though PB likely can understand her as well.

Appearance
Lady is a long unicorn-like creature. She has rainbow colored stripes along her body and a blond mane. She also has big round eyes similar to Jake's. She also has a single, sharply-pointed horn. Her mom has a long body like hers, unlike her father. This means that she inherited her length from her mother, since in the episode "Her Parents" her mother and father don't find it odd that Jake can stretch or is long like the females before they know he is a dog. Because Ethel's body is longer than Lady's, and Bob's body is much shorter, it is also possible that Lady has inherited both traits resulting in a body length that is in-between (longer than Bob,shorter then Ethel).

Abilities
Lady has the ability to fly and can use her horn to change the color of anything she wants. In the episode "My Two Favorite People," Lady Rainicorn explains to Finn that she can fly because her body can intercept beams of reflected light from the sun and "dance around" on them. In the same episode, she is shown to live in a stable in the Cotton Candy Forest. She can also speak a different language by using the Universal Translator. Also, Lady can stretch longer or shorter as you can see when she lands. She may have Stretchy Powers. It is revealed in "The Creeps" that she can phase through walls and also carry people while phasing. She also can play the viola, like Jake.

Personality and Traits
Lady is laid-back and likes to interact with Jake and Princess Bubblegum. She is considered Princess Bubblegum's companion, like Jake is Finn's companion. She's rarely sad or angry. In the Animated Short, she was seen crying and in the episode "My Two Favorite People," she becomes sad when Jake plays the viola with Tiffany. She does not speak Korean in the Animated Short; she only makes soft cooing sounds (or, near the beginning, hysterical screaming coos). However, Jake seems to understand what she says when he talks to her. She believes she is smarter than Jake. She may also have a fondness for Power Rings although she seems to have no fingers.

Jake
On the official website in Lady's description, it says Jake is her boyfriend and that they get along so well because of their common interest in the viola. This relationship began in the short when he and Lady Rainicorn were flirting and sharing interests. At the beginning of "Slumber Party Panic," she is shown being playfully chased by Jake, and later in the episode, they both seem to very much enjoy playing "Seven Minutes in Heaven" (which is a game where two people are locked in a closet together to kiss for 7 minutes, sometimes leading to other things.) In "My Two Favorite People," Lady recalls a time when she and Jake ran naked through a farmers field, causing Jake and herself to blush which may indicate some level of intimacy in their relationship. In "My Two Favorite People," Jake is torn between his desires to go adventuring with Finn and hanging out with his girlfriend. Lady later says she loves Jake "because he's an idiot" and that he makes her "feel like a genius." In "Video Makers", Jake gets very jealous when Mr. Cupcake flirts with Lady and becomes violently protective of her. The relationship appears to be rather serious, as he also was worried about his impression on her parents and even went to say he was studying Rainicorn history for their future children. Lady's mother Ethel referred to Jake as hers and Bob's future son-in-law, hinting that she can see them getting married.In Go with me Jake takes her to the movienight and they ended up making out through the whole movienight.

Princess Bubblegum
Lady is usually seen with or near Princess Bubblegum in the Cotton Candy Forest in the Candy Kingdom. In the Animated Short, she shows great concern when the princess is abducted by Ice King, and even tried to rescue her from him. She is sometimes described as the princess' pet. In "What Have You Done?", Lady flew the princess to the Ice Kingdom so she could ask for Ice King's help in ending the plague in the Candy Kingdom, and showed great disgust at him when he mistook their pleas for help for flirting. Lady even speaks to him at this time, saying "Verily, you are a creature unworthy even of my lady's disdain."

Finn
In the beginning of episode "My Two Favorite People," Rainicorn and Finn's relationship is awkward because, even though she can understand spoken English, Finn can't understand what she is saying, but they form a friendship when she helps Finn and Jake recover the Universal Translator at the bottom of the lake guarded by Lake Knights. When Jake puts the translator around Rainicorn's neck, Finn can only understand her with Old Man mode (the Universal Translator is limited to 3 speak modes: Old Man, Nerdy Alien, and Nightmare). However, Old Man is the only voice Finn can understand, but he finds it amusing. Finn is impressed by her ability to fight, as they ward off the guardians that protect the translator on the pile of gold and jewels and other monsters in the episode, "My Two Favorite People". They soon become good friends, without any awkward misunderstandings in communication but Jake becomes jealous of how much time Finn and Lady Rainicorn spend together.

Ethel
Ethel Rainicorn is Lady's mother, who appears in "Her Parents". They may have a mother-daughter relationship, she is very shy to everyone but Jake, Bob, and Lady. She referred to Jake as her and Bob's future son-in-law.

Bob
Bob Rainicorn is married to Ethel, and is Lady's father. He might have a close relationship with Lady. Bob appears in "Her Parents", and is very impressed with "Rainicorn" Jake.

Mr.Cupcake
Mr.Cupcake has a crush on Lady Rainicorn because he was seen flexing his muscles (Flirting) in front of Lady Rainicorn in Video Makers to impress her that he is a very strong guy.

Quotes
See Lady Rainicorn/Quotes

Trivia

 * In one room of the royal castle, there are two pictures of Lady Rainicorn on the wall: One of her upper half, and one of her lower half.
 * Two Rainicorns appeared in the Double Rainbow promo. It may be that they are both Lady Rainicorn somehow doubling herself using the light.
 * There are many episodes where Lady Rainicorn appears where she doesn't do so physically: she shows up in photographs owned by Jake such as in "Rainy Day Daydream," "What is Life?," "Still," "The Eyes," "No One Can Hear You" and by Princess Bubblegum in "What Have You Done?," as well as graffiti art in the title card for "Heat Signature" and in Jake's mind in "Mortal Folly," among other cameos.
 * Her original name was "Lady the Rainicorn."
 * Unlike her parents, Lady Rainicorn chooses to not wear a Universal Translator to speak to people of Ooo. Generally, her words are known and translated by those who understand her, like Jake.
 * Even though Lady Rainicorn looks friendly, she is actually a tough fighter, as shown when she saved Finn from Lake Knights.
 * In the animated short, she spoke in a type of gurgling language instead of in Korean.
 * In "The Real You," PB is seen in the beginning with a yellow T-shirt with a red rainicorn on it. The rainicorn may be Lady.
 * Lady Rainicorn has a gender-swapped version of herself: Lord Monochromicorn.
 * Her favorite drink is iced latte as shown in "Video Makers."
 * Since her name is "Lady" Rainicorn, it is possible that she is a figure of authority among Rainicorns, as well as Candy People.
 * In "Apple Thief" Jake cooks Finn traditional Korean food that he learned from Lady Rainicorn.
 * In "From Bad to Worse" when Jake apologized to Lady Rainicorn for biting her, she responded, "I like it when you bite me," causing Jake to blush.
 * Despite being based on a rainbow, Lady Rainicorn's body does not display any orange
 * In "From Bad To Worse," she states in Korean, "I want you bite me," causing Jake to blush, showing a serious relationship between them.

Episodes featured
« indicates where Lady Rainicorn has a spoken role with human language.

Major appearances

 * "My Two Favorite People" «
 * "Her Parents" «
 * Animated Short
 * "From Bad to Worse" «

Minor appearances

 * "Slumber Party Panic" «
 * "The Enchiridion!"
 * "What Have You Done?" «
 * "Power Animal"
 * "Go With Me"
 * "Video Makers" «
 * "Mortal Folly"
 * "The Creeps" «
 * "Holly Jolly Secrets Part II"
 * "Dad's Dungeon"