King Tirian rules Narnia in C.S. Lewis's final Narnia novel, The Last Battle.
Published in 1956, The Last Battle is the seventh and final published volume of The Chronicles of Narnia. Tirian is the last king of Narnia, and the story begins when he learns that an ape named Shift is using a false Aslan to manipulate the kingdom. The resulting crisis leads to the final battle and the end of the old Narnian world.
Narnia is distinct from neighboring lands such as Archenland and Calormen. Telmar is another kingdom connected to Narnian history, especially in Prince Caspian, but it is not Tirian’s realm. These similar place names are a common source of mix-ups for readers.
The novel is notable for its apocalyptic structure and for bringing together characters, symbols and themes from earlier Narnia books. It closes the main sequence rather than setting up another published sequel by Lewis.