War Queen or War King was a title held by the leader of the Great Houses during the War.
One Head of the Presidency, called "Self-Ruler" and "Imperator" in his own time, would have been called War King if he had lived later. He even considered the title himself. (PROSE: The Return of the King)
Six years before the War, an ex-renegade was declared War King on the original Homeworld. (PROSE: Timeline)
On one Gallifrey, two years before the War (PROSE: Nine Homeworlds, Timeline), Romana was Lady President, War Queen, and Mistress of the Nine Gallifreys. (PROSE: The Shadows of Avalon)
After more than fifty years of the War, Lolita consumed the War King and declared herself the new War Queen. (AUDIO: Words from Nine Divinities)