He is the unofficial leader of the Seiryu Seven and is not only the most powerful of the Seiryu Warrios, but he is the most powerful Celestial Warrior, besting even Tamahome's skills with great ease. He is capable of energy blasts, enhanced speed, and is an accomplished sorcerer and the general of Kutou. He is heavily charismatic and is why Yui Hongo thought that Miaka Yuki and her were no longer friends. However, he sees his allie and even Yui as mere tools for his goals. The only person he seemed to care about was the Seiyru warrior Soi, which is shown when he is greatly upset when she is killed in battle.
At first, Nakago wanted to take over the entire Universe of the Four Gods and even betrayed the Kutou Emperor, killing him. However, he saw the illusion Tomo made from Miaka's memories and sought to conquer the real world.
He planned to use Yui's status as the Priestess of Seiryu in order to gain immortality. His plan failed when Yui uses her final wish to undo the seal on Suzaku. Nakago is only defeated when Miaka seals Seiryu's power, making Nakago powerless and vulnerable to Tamahome. Nakago accepts his fate and is killed when Tamahome punches a hole through his chest. Before Nakago dies, Tamahome is able to see Nakago's tragic past. When Nakago was a child, his people were invaded by Kutou and his powers manifested and he accidentally killed his mother and the Emperor took him in as a Celestial Warrior.