Plue

Plue (プルー Purū) is a Silver Key Celestial Spirit with no actual combat abilities, stated to be usually kept as a pet for less powerful Mages, including Lucy herself as his owner. His key was sold for 20 000.

Appearance
Plue is a short and stout white creature with bland eyes and a golden horn-like nose reminiscent of a carrot, giving him a slight appearance of a snowman. His body is often shaking nervously, though this doesn't always occur. He cannot speak besides saying "puu-puun", although Natsu seems to be able to understand him anyway. He mostly communicates by using gestures and motions which Lucy finds adorable.

Personality
Because he is not made for combat, Plue serves as a cute companion instead. He is very obedient and ready to help Lucy whenever she needs his help. Along with that, he enjoys sweets and shares a close friendship with Happy and is often seen teasing Lucy and Loke along with him. He is also very apologetic, as he immediately apologized to his owner after harming her under the influence of Sherry's Magic.

Daybreak arc
In order to show Natsu and Happy how contracts with Celestial Spirits are made, Lucy summons Plue for the first time and demonstrates it. However, because of Plue's peculiar appearance, Natsu and Happy see him as a failure. When Plue "speaks" for the first time, Natsu seems to be able to understand him, while Lucy cannot. Plue then suggests Natsu to form a team with Lucy, being the first one to do so.

Lullaby arc
Plue is seen beside Lucy when Mirajane tells her to go on a job with Natsu, Gray and Erza. Lucy carries Plue while seeing Gray and Natsu arguing. Plue is later still being carried while Erza discusses with the group about the Dark Guild Eisenwald and Lullaby on the train. He is seen soaked when Lucy shakes in fear after hearing about Erigor. Afterwards, Plue is seen eating along with everyone else.

Galuna Island arc
In a battle against Sherry Blendy, Lucy purposely summons Plue, knowing the latter will use her magic on him. Once under Sherry's control, Plue's eyes glow as he runs aggressively towards Lucy. Due to his noncombatant nature, however, he is unable to harm Lucy despite the flurry of kicks and punches he delivers. Once Sherry releases him from her magic, he immediately apologizes to Lucy and returns to the Celestial Spirit World afterwards.

Loke arc
After arguing with Loke, Lucy leaves with Happy and Plue, who seems to recognize Loke. Later, Plue, along with all of Lucy's Spirits, is summoned in order to persuade the Celestial Spirit King to let Loke return to the Celestial Spirit World.

Daphne arc
Note: Events in this arc occur only in the anime and do not constitute canon material.

Tenrou Island arc
Note: Events in this arc occur only in the anime and do not constitute canon material.

X791 arc
Upon returning to the present time, Lucy heads home with Plue but is not allowed in her apartment because of the seven years of rent she owes to her landlady. Lucy then talks to Plue about her father, whom she finally decided to visit.

Key of the Starry Sky arc
Note: Events in this arc occur only in the anime and do not constitute canon material.

Grand Magic Games arc
While training for the Grand Magic Games, Lucy and her friends are brought by Virgo to the Celestial Spirit World, where the Spirit celebrate their return from Tenrou Island. During the festivities, Plue greets Carla and Happy, together with other dozens of Nikora's behind him, who lift the two into the air. Plue then dances with Happy as Lyra plays her harp.

Much later, Plue appears at the King's banquet following the Mages' victory against Future Rogue Cheney's Dragons and is soon caught up in the verbal brawl, where the Mages discuss which guild Yukino Agria will join.

Eclipse Celestial Spirits arc
Note: Events in this arc occur only in the anime and do not constitute canon material.

Sun Village arc
After returning back to Magnolia, Lucy resumes her everyday life, this involving summoning Plue and going on walks with him. One day, as Lucy and Plue walk back home, Lucy remembers that she still hasn't paid her rent and says that she needs to go on a job soon. When Lucy opens her apartment's door, she and Plue see Erza, Carla and Wendy comfortably sitting on her couch.

Avatar arc
One year after Fairy Tail's disbandment, Plue is helping Lucy in tracking down other members of the guild, with the latter starting to cry after reminding herself of the times she spent with them.

Alvarez Empire arc
After Lucy's team manages to retrieve Makarov from the Alvarez Empire and take him back to the newly rebuilt Fairy Tail guild with them, Plue hangs out with Lucy and Levy as they dine and talk about the liveliness of the guild having returned.

Magic and Abilities
Enhanced Speed: Plue is shown to have enough speed to catch up to Lucy while they were running from a mysterious figure, as well as to dance faster than one of Daphne's Lizardmen.

Immortality: As a Celestial Spirit, Plue cannot die, unless he is somehow forced to stay in the Human World.

Fairy Academy: Yankee-kun and Yankee-chan
Plue, along with other students of Fairy Academy, heads for his classes during the morning of Lucy's first day at the academy.

Megane-Fairy
Lucy lends Plue's Gate Key to Daichi Shinagawa so that the latter may summon him in order to demonstrate his ability to perform Magic to Makarov. However, Shinagawa ends up summoning a deformed version of the Spirit instead.

Welcome to Fairy Hills!
Plue accompanies Lucy in investigating a job request from Fairy Hills where they meet their, Hilda, who assigns the job for Lucy.

Happy in Boots
Plue is the first "animal" that Happy captures with his sack and also the first present to the king and princess of the kingdom.

Welcome to Fairy Hills!!
Plue accompanies Lucy in investigating a job request from Fairy Hills where they meet Hilda, the client, who assigns Lucy for the job. He later watches as Hilda immediately changes Lucy's normal clothes into that of a cat outfit after Lucy accepts Hilda's strange job.

Fairy Academy - Yankee-kun and Yankee-chan!
Plue appears as the Fairy Academy principal during the assembly called by Carla as a lecture to the delinquent students. He delivers his speech in a dance that is only understood by Natsu and Carla, both moved to tears over Plue's apparently very inspirational spiel.

Fairy Tail Gekitotsu! Kardia Daiseidou
Plue appears as a playable character in Nintendo DS Game Fairy Tail Gekitotsu! Kardia Daiseidou. In this game, Plue possess the following moves:
 * Main:
 * Sub 1:
 * Sub 2:
 * Sub 3:
 * Super:

Trivia

 * Plue is the only "dog" Happy likes.
 * Happy plays a trick on Lucy by feigning a voice for Plue. Happy makes a reference to Rave Master, saying that Plue is the servant of a hero with a sacred stone, Haru and the Rave respectively.
 * A special restriction made by Hiro Mashima stated that the number of lines on Plue's nose must be 5, no more, no less.
 * The S-Class Mage Mirajane considers him as the strongest spirit ever.
 * Plue's character was featured in Hiro Mashima's previous work, Rave Master.
 * In the English dub of the first episode, Lucy called Plue's key "Canis Minor the White Dog" instead of "Nikora the Canis Minor".
 * In the Manga, Lucy called Plue's key "White Doggy" instead of "Nikora the Canis Minor".