Mog (モグ, Mogu?) is a recurring character from the Chocobo series and is the most famous moogle in the series. He always attempts to steal the limelight from Chocobo, the series' main protagonist, though Chocobo mostly ends up foiling his plans. Nevertheless, Mog sticks with Chocobo and the two are fast friends.
Mog is a greedy little moogle who jumps at the chance of hoarding treasure for his own. Whenever he travels in an adventure with Chocobo, Mog will always cook up a plan behind the bird's back for his own gain.
Named "Atla" (アトラ, Atora?), Mog travels with Chocobo to a village. After helping Chocobo save a chocobo villager from an evil crystal that possessed him, Mog himself is possessed. He is later saved by Chocobo and Chubby Chocobo, who proceed to destroy the crystal.
Mog travels the world with Chocobo as treasure hunters who explore dungeons around the world. Mog is egoistic and is always looking for a way to surpass Chocobo. He has high HP growth and his physical attacks are average. He can sometimes steal items from enemies whenever Chocobo doesn't have any in his inventory.
Mog had commissioned Cid to create a racing machine to beat Chocobo in a race, but Cid had forgotten all about it; partly because the inventor was busy inventing Jet-Blades for Chocobo. Mog got his racing machine; a scooter with custom-made Moogle horn, and challenges Chocobo to a race, only to be beaten. Cid explains to an angry Mog that the Blue Crystal on Chocobo's leg helped Chocobo win, and that if they travel together around the world, they will surely find other Blue Crystals. Mog jumps at the chance and joins Chocobo.
Mog's ability is "Flap", which allows him to fly over obstacles for a limited amount of time. He drives the Mog-Mobile R2, which is easy to handle.
Mog is just an ordinary moogle. However, he has delusions of grandeur, and likes to dress up as his alter ego, "Dueler X" (ポップアップヒーロー, Poppu Appu Hīrō?, lit. Pop-Up Hero). As Dueler X, Mog believes he is the greatest card battler ever, and teaches Chocobo how to play cards and gives him decks to work with. Everyone knows that Dueler X is really Mog, but Mog cannot accept this.
In this game, Mog assumes five alter egos; Dungeon Hero X (ダンジョンヒーローX, Danjon Hīrō Ekkusu?), Pop Up Hero X (ポップアップヒーロー, Poppu Appu Hīrō?), Merchant Hero X, Romantic Hero X, and Robber Hero X. Four of Mog's alter egos give Chocobo help on his adventure in different way. In a book that can be found in the empty house after the game's ending, it is said that Mog was found almost dead by Shirma's mother, Elena, on Christmas Eve. Mog asked Elena to cast a spell on him, to make him stronger and unbeatable. Elena answered that she didn't know such a spell but promised to give him a present. The day after, Mog found his purple mask under the Christmas tree sewn by Elena who told him to became a super-hero thanks to it. This is how Dungeon Hero X was born. Mog is voiced by Kumiko Watanabe in the Japanese version and Brina Palencia in the English version.
- As Dungeon Hero X, Mog will appear at the beginning of each dungeon and give advice about dungeons and abilities. Also, he will try to stop the player if they steal the Thief's Memory that's behind Merchant Hero X. He uses moves like X Cannon and kicks that send Chocobo flying backwards. The player won't have to beat him, just make it to the stairs.
- Pop Up Hero X teaches Chocobo about Pop up Duels in the Mog House. The revealing of this alter ego is what tips players off that all the Hero Xs are the same person. Mog, not as any alter ego, appears before Chocobo when he touches the Pop Up duel arcade game. He tries to cover this up, unsuccessfully.
- Merchant Hero X will sell items to Chocobo in any dungeon, if the right duel trap is stepped on. He is doing a campaign where he will buy items from Chocobo at a higher price than regular merchants. He also sells a bejeweled collar in the storage house.
- Romantic Hero X will give the player Pop Up cards if they tell him a Romantic Phrase obtained after restoring someone's memories, and a letter appears in the mailbox at Stella's Farm. There are also Romantic Phrases in the hidden Secret Letters, such as one under the steam train near Stella's Farm.
- Robber Hero X will fight Chocobo in a dueling room in some dungeons. True to his name, Robber Hero X will move straight for Chocobo and attempt to steal an item from him with Mug X. If the attack is successful, Robber Hero X will gloat about his successful theft and move for the exit. If he reaches the exit, he will escape the dungeon with Teleport, taking Chocobo's item with him.
Mog appears as Cid's friend. Because of this friendship, there's always a moogle in each of Cid's Alvancia picture books.
- Mog's English voice actress in Final Fantasy Fables: Chocobo's Dungeon also voiced Nina Tucker from another Square Enix project: Fullmetal Alchemist and its reboot Fullmetal Alchemist: Brotherhood.