The title of Territory Lord (領主) is granted to those who have control of a Fragment. While the title is synonymous with Game Master in many respects, the title of Territory Lord can only be inherited or passed down, as opposed to Game Masters being appointed simply for creating or opening a gameboard.
The Territory Lord title is also much more formal than that of other titles, being represented by a golden ring and having a ceremony dedicated to the succession.
Known Territory Lords
MAJOR UMINEKO SPOILER WARNING
This article or section contains untagged major spoilers for all of Umineko When They Cry, possibly including the manga. Readers who have not completed the story are advised not to proceed further.
While Erika never truly became a Territory Lord, she attempted to do so by marrying BATTLER after he had become trapped in a Logic Error and was rendered comatose.