Mogu's clan built its world underground and lives there quietly. None of the clan have ever appeared in the front lines of history, but their ability to dig several thousand feet a day is known throughout the land. They are small, but powerful and can wear heavy equipment. Mogu is silent and shy, but he has a strong sense of responsibility. When he fights, he proves himself to be an incredibly brave warrior.
Mogu's tribe was enslaved by the Dark Dragon's and forced to dig up the ruins of the Obelisk. During this time, Mogu was attacked by a rogue member of his tribe named Mote, who split apart his psyche in a dream world in order to prevent him from helping Ryu get into Spyre to get the Sky Key Jade had ordered Mote to retrieve. The party had to obtain a special artifact to travel into Mogu's dream world and reunite his psyche to battle the demon Mothro. Afterwards, Mogu joined the party and helped them obtain the Sky Key and defeat Mote.
As a member of the Dirt-Eating Clan Mogu's most prominent skill is his ability to dig holes with his sharp claws. Mogu's hole digging allows access to certain items as well as access to areas that are otherwise inaccessible.
Mogu an average fighter who doesn't necessarily excel at anything and is often overshadowed by the rest of the party as he is the last party member to join. Mogu is not a component of Karn's various fusion forms either. His weapon and equipment choices allow him to be a capable fighter on the frontlines but his low HP and mediocre stats makes him a liability. Mogu has one spell called Dig that allows the party to flee from battle.
Mogu is the only party member barring the legacy characters (Ryu, Nina, and Bleu) who is not used for any of Karn's fusion spells.
He is called Mog in the Japanese version because Mogura is the Japanese word for mole and Mog is a shorten version of the name.
Two characters named Mogu and Bo (named Gilliam) make an appearance at the start of Breath of Fire III being the ones in Dauna Mine that unwittingly free Ryu (in a Whelpform) from his slumber, as well as the first enemies Ryu fights in the game. This is clearly a reference to Mogu and Bo from Breath of Fire.