Although he initially comes off as a much older character, Red XII is actually only equivalent to a 15-16 year old in human years. He joins the group out necessity, as he is being held captive in the Shina Building. After the team escapes the Shinra Building, and Midgar completely, Red XIII tags along until he can make it back to his home, Cosmo Canyon. Upon his arrival at Cosmo Canyon, Red XIII announces that this is the end of his journey, but his grandfather, Bugenhagen, has a different idea. Red XIII believed his own father was a coward, who allowed the Gi tribe to attack his village and all but wipe out his race. Bugenhagen takes Red XIII to his father’s petrified remains to show him that the complete opposite was true, his father was a great warrior who gave his life to protect Cosmo Canyon. After seeing this, Red XIII vows to become a great warrior like his father, and joins the group permanently to help them in their quest to save the planet and defeat Sephiroth.
“I am Nanaki, son of Seto… Warrior and protector of Cosmo Canyon.” – Red XIII