Tirian is the son of King Erlian and seventh in descent from King Rilian, and has the distinction of being the last King of Narnia. In 2555 NT when he was in his twenties, Tirian is near Cair Paravel with his dear friend Jewel the Unicorn when he hears tale that Aslan has appeared in Narnia. He's excited at the prospect of finally being able to see Aslan, and is angry and upset when he is advised that the tale of the Lion's coming is a lie. When Tirian witnesses the destruction of a Dryad by the hands of Calormenes, he and Jewel set out to discover the truth. When it is apparent that the Calormenes have enslaved Narnians and are cutting down trees, he becomes enraged and he and Jewel kill two unsuspecting Calormen drivers.
Demoralized and deeply saddened by his rash act of anger, he turns himself over to the Calormenes expecting to be brought before Aslan. Instead, he discovers that Shift and Rishda Tarkaan are deceiving the Narnians, and when he tries to speak against this, he is gagged and tied to a tree. There, he can observe some of the goings on at the Stable.
Smaller creatures of Narnia later come to his aid with food and drink, but dare not untie him for fear of "Tashlan's" wrath. When later alone, Tirian in desperation calls on the aid of the children from the old tales of Narnia. He is thrown into a deep dream-like state and finds himself in the midst of a gathering of strangers, although he cannot speak but can only motion, and the dream soon fades away. As soon as he awakes, he finds Eustace and Jill nearby, having just arrived to answer his call. They free him, and Tirian leads them to a Narnianguard tower where they find food and refreshment.
Later the next day Tirian and the two children disguise themselves as Calormenes and sneak back to the Stable to free Jewel and then go back to the guard tower. Tirian intends to set out for Cair Paravel to find aid, but before go far they are met by Roonwit theRaven, who informs them that Cair Paravel has been attacked and overthrown by Calormenes from the sea.
Tirian, knowing that there is nothing left to do but go back to the Stable and try and overthrow the Calormenes himself and most likely die trying, attempts to get Eustace and Jill to either go back to Narnia or at least flee toArchenland. They refuse, however, and they and a small band of loyal Narnians head back to the Stable for the last battle.
During the course of events there, Tirian succeeds in throwing Shift through the Stable door and when entangled in a fierce sword duel with Rishda Tarkaan, he is pushed into the Stable but also takes Rishda with him. There, he witnessesRishda's fate at the hands of the Calormen god Tash.
He then finds himself in the New Narnia and witnesses the destruction of the Old Narnia. Then he and all the other Friends journey to the Great Reunion, where Tirianreunites with his father.