Takk is an original character created for Legendary Guardian and has no basis in cannon from Square Soft in Final Fantasy X. He is mentioned in several chapters of LG and also appears in Braska's Journey.

Part of a group of four Summoners and their Guardians that accompany Auron’s uncle, Youke, to the Calm Lands; Takk is protector of Jarden. The pair become fast friends with the Second of Bevelle. After Jarden mysteriously obtains a new Aeon, the tide of battle is turned and Youke helps the Summoner and Guardian lead the vanguard party.

Later, Youke mentions Takk to his own Summoner – the Maester Umaro. As the two prepare to ascend Mt. Gagazet, Auron’s uncle mentions that Jarden fell to fiends before reaching the mountain summit. His Guardian, Takk, survived the fateful trek and returned to his people. He teaches blue magic and fighting skills to the "cubs" and serves as weapons master for the Gagazet shrine.

In addition to being a warrior and Guardian, Takk has another special purpose in my stories. He is the father of Kimahri.