feat(tyrant): add arena boss succession

design/concepts/game-state-machine.md

@@ -8,31 +8,32 @@ description: Defines lifecycle, succession, selection, and pause behavior for a
 
 ## Lifecycle
 
-The game begins unstarted. An administrator starts it by assigning the first Tyrant; the administrator may explicitly assign the first Vigilante or allow selection from eligible recently active players. A running game may be paused without deleting its state and later resumed.
+The game begins unstarted. An administrator starts it by assigning the first Tyrant; the administrator may explicitly assign the first Vigilante or leave that role vacant for the blue arena challenge. A running game may be paused without deleting its state and later resumed.
 
 Pausing freezes gameplay progression, role inactivity checks, pending-selection deadlines, ability cooldowns, and daily-use timers. Role and class effects are suppressed while paused and restored on resume.
 
 ## Tyrant succession
 
-When a player directly kills the Tyrant, that killer becomes the new Tyrant. When no player is credited with the death, an eligible opted-in player active during the preceding 24 hours is selected randomly. The former Tyrant is excluded when another candidate exists.
+When a player directly kills the Tyrant, that killer becomes the new Tyrant immediately. When no player is credited with the death, or when the Tyrant becomes inactive or relinquishes, the reign ends and the Tyrant role remains vacant for the shared arena challenge. The former Tyrant may compete again under the same rules as other opted-in participants.
 
-Every Tyrant death ends the reign, clears all role-side assignments, resets the former Tyrant's reign progression, and leaves the Vigilante role open for the arena challenge. The new Tyrant receives one starting unlock choice.
+Every ended Tyrant reign clears all role-side assignments and resets reign progression. The shared arena presents the Tyrant challenge first with a red particle boundary. Its winner becomes Tyrant at level zero with one starting unlock choice; only then may a vacant Vigilante role open the blue challenge at the same location.
 
 ## Vigilante succession
 
 Every Vigilante death ends that assignment regardless of cause. Vigilante inactivity and relinquishment also end the assignment, and every new Tyrant reign clears the previous assignment. Followers are cleared rather than transferred.
 
-While the game is running with an active Tyrant and no Vigilante, an administrator-configured arena opens. One eligible opted-in non-Tyrant player at a time may challenge the arena boss. Defeating it assigns that player as Vigilante. Leaving, disconnecting, or dying resets the fight without preventing an immediate retry. Without an active Tyrant or configured arena, the role remains vacant and no boss exists.
+While the game is running with an active Tyrant, no open Tyrant challenge, and no Vigilante, the administrator-configured arena opens its Vigilante challenge. One eligible opted-in non-Tyrant player at a time may challenge the arena boss. Defeating it assigns that player as Vigilante. Leaving, disconnecting, or dying resets the fight without preventing an immediate retry. Without an active Tyrant or configured arena, the role remains vacant and no boss exists.
 
 A Tyrant earns progression from a Vigilante death only when the Tyrant personally killed the Vigilante.
 
 ## Pending selections
 
-An offline randomly selected Tyrant has 24 hours of unpaused time to log in and confirm the assignment. Failure causes another Tyrant selection. When no eligible Tyrant candidate exists, the position remains vacant and selection retries periodically. Vigilante vacancies use the arena rather than pending random selection.
+New random and pending role selections are not created. Legacy pending Tyrant or Vigilante selections are cleared into the applicable arena vacancy without granting a role. A Tyrant vacancy has priority, so the two role challenges cannot run concurrently.
 
 ## Related stories
 
 - [Start, pause, and administer the game](../user-stories/us-001-start-pause-and-administer.md)
 - [Transfer and reset the Tyrant role](../user-stories/us-002-transfer-and-reset-tyrant.md)
-- [Handle inactivity and pending selections](../user-stories/us-010-handle-inactivity-and-selection.md)
+- [Handle inactivity and arena vacancies](../user-stories/us-010-handle-inactivity-and-selection.md)
 - [Claim the Vigilante role in the arena](../user-stories/us-019-claim-vigilante-in-arena.md)
+- [Claim the Tyrant role in the arena](../user-stories/us-020-claim-tyrant-in-arena.md)

design/concepts/persistence-model.md

@@ -6,7 +6,7 @@ description: Defines the durable state and timekeeping needed to restore a Tyran
 
 # Persistence Model
 
-State is keyed by player UUID while retaining the latest known player name for display. Durable global state includes lifecycle status, current and pending role holders, selection deadlines, paused durations, the current Tyrant reign, and the administrator-configured Vigilante arena center. Active boss and challenger entities are transient and are reconstructed or reset from authoritative role and arena state after restart.
+State is keyed by player UUID while retaining the latest known player name for display. Durable global state includes lifecycle status, current and pending role holders, selection deadlines, paused durations, the current Tyrant reign, and the administrator-configured Vigilante arena center. Active Tyrant or Vigilante challenge bosses and challenger entities are transient and are reconstructed or reset from authoritative role and shared-arena state after restart.
 
 Durable player state includes participation status, opt-out deadline, login history, role or class, Tyrant level, purchased unlocks, unspent choices, Follower relationship, ability cooldowns, daily intelligence use, bound-item delivery state, and captured mobs.
 
@@ -18,3 +18,4 @@ Elapsed-time rules use UTC instants. Paused time is excluded from timers. Saves
 - [Configure and persist game state](../user-stories/us-012-configure-and-persist-state.md)
 - [Use class ability items](../user-stories/us-014-use-class-ability-items.md)
 - [Claim the Vigilante role in the arena](../user-stories/us-019-claim-vigilante-in-arena.md)
+- [Claim the Tyrant role in the arena](../user-stories/us-020-claim-tyrant-in-arena.md)

design/concepts/role-and-class-model.md

@@ -8,7 +8,7 @@ description: Defines Tyrant-side classes, Vigilante-side membership, progression
 
 ## Roles and affiliations
 
-A running game has one active or pending Tyrant. It has at most one Vigilante, and a vacant Vigilante role remains open until an eligible player wins the configured arena challenge. The Vigilante may recruit Followers through invitations that require acceptance. The Tyrant may assign the Assassin, Fixer, and Tamer classes after unlocking them.
+A running game has at most one Tyrant and at most one Vigilante. A vacant Tyrant role takes priority in the shared arena; after its winner becomes Tyrant, a vacant Vigilante role may use the same arena. The Vigilante may recruit Followers through invitations that require acceptance. The Tyrant may assign the Assassin, Fixer, and Tamer classes after unlocking them.
 
 Role alignment and Tyrant-side class are independent. A Vigilante or Follower may simultaneously hold one Tyrant-side class, allowing divided loyalties. A player cannot simultaneously be the Tyrant, Vigilante, and/or a Follower, and cannot hold more than one Tyrant-side class. Each Tyrant-side class may be assigned to only one player at a time. Opted-out players are ineligible for every assignment.
 
@@ -37,3 +37,4 @@ Vigilante Follower scaling is capped by default at Strength V and Resistance IV,
 - [Assign unlocked classes](../user-stories/us-004-assign-unlocked-classes.md)
 - [Support the Vigilante and Followers](../user-stories/us-008-support-vigilante-and-followers.md)
 - [Claim the Vigilante role in the arena](../user-stories/us-019-claim-vigilante-in-arena.md)
+- [Claim the Tyrant role in the arena](../user-stories/us-020-claim-tyrant-in-arena.md)