Crux is a Celestial Spirit owned by Lucy Heartfilia. It is unknown if Crux can be used for combat purposes. However, it is known that Crux has the ability to search for information about Celestial Spirits and their owners by sleeping. His nickname is Crumudgeon.

Across the Fiore kingdom, wizards join guilds and make their pay by filling magical needs—but one guild has a reputation as the roughest, rowdiest, most dangerous of all: Fairy Tail! 
When four young Fairy Tail members unite, their bond is forged by a power found in neither muscle nor magic and grows stronger with every mission. Whatever you do, don't mess with these friends or you'll get a taste of Natsu's flaming fist or Gray's ice hammer, suffer a painful blow from one of Lucy's celestial spirits or catch the edge of Erza's mighty blade! Whether they're stopping demons from devastating the world or wrestling in the mess hall, this mystical team manages to inflict as much damage to their rivals as they do to the surrounding area! 
 
(Source: Funimation)

[Wiki (jp)](https://ja.wikipedia.org/wiki/木村雅史)

The Grand Magic Games reaches its climax following Natsu Dragneel and Gajeel Redfox's stunning victory over Sting Eucliffe and Rogue Cheney of the Sabertooth guild. This success pushes the Fairy Tail guild closer to being crowned the overall champions, but obtaining victory isn't the only challenge they face. A mystery still surrounds a hooded stranger and the ominous Eclipse Gate, leaving more questions than answers. More crazy adventures are on the horizon for Fairy Tail as their destructive antics and joyful rowdiness continue unabated. Their greatest trial is quickly approaching, but united as a family, the guild will always be ready to face any threat that comes their way.

Cute girl wizard Lucy wants to join the Fairy Tail, a club for the most powerful wizards. But instead her ambitions land her in the clutches of a gang of unsavory pirates led by a devious magician. Her only hope is Natsu, a strange boy she happens to meet on her travels. Natsu’s not your typical hero—he gets motion sickness, eats like a pig, and his best friend is a talking cat. With friends like this, is Lucy better off with her enemies?
 
(Source: Kodansha USA)
 
Note: Includes 4 extra chapters.

OVAs bundled with special editions volumes of the manga. 
 
1. Youkoso Fairy Hills! 
Lucy comes across a mysterious written request. The client is looking for an object that is in Fairy Tail's female dormitory, Fairy Hills. To verify the request, Lucy visits Fairy Hills, and discovers that the client is Hilda, the dormitory head who is looking for a "shining treasure." Meanwhile, Natsu and the other guild members are cleaning their pool. 
 
2. Yousei Gakuen: Yankee-kun to Yankee-chan 
The anime adaptation of the manga side story "Yousei Gakuen Yankee-kun to Yankee-chan," which puts the characters of Fairy Tail in a school setting. The title is a parody of Miki Yoshikawa's "Yankee-kun to Megane-chan." 
 
3. Memory Days 
An all-new original story storyboarded by Hiro Mashima, the author of Fairy Tail, released on February 17, 2012. "Natsu's Secret" is going to be revealed in the "Past World"?! Guided by a "magic book" that's lying in the Guild's storage room, Natsu, Lucy, Happy, Gray, and Erza have traveled back into the past!! 
 
4. Yousei-tachi no Gasshuku 
Natsu, Lucy, and the others go to a training camp for the Grand Magic Games. While there, the Fairy Tail Guild take a much needed break at the beach and hot spring. 
 
5. Dokidoki Ryuuzetsu Land 
Adapting the chapter 298. The story is set during the Grand Magic Games when various guilds gather at the pool for some fun (and the chaos that ensues).