diff --git a/shared/tests/turn.characterization.test.js b/shared/tests/turn.characterization.test.js
index 18e07c2..a9e51b6 100644
--- a/shared/tests/turn.characterization.test.js
+++ b/shared/tests/turn.characterization.test.js
@@ -77,11 +77,12 @@ describe('startEncounter', () => {
     expect(patch.currentTurnParticipantId).toBe('b');
   });
 
-  test('inactive excluded from turn order', () => {
+  test('inactive stays in turn order slot (1-list model)', () => {
     const ps = [p('a', 5), p('b', 15, { isActive: false }), p('c', 10)];
     const { patch } = startEncounter(enc(ps));
-    expect(patch.turnOrderIds).toEqual(['c', 'a']);
-    expect(patch.currentTurnParticipantId).toBe('c');
+    // 1-list: all participants sorted by init (active+inactive), inactive stays in slot
+    expect(patch.turnOrderIds).toEqual(['b', 'c', 'a']);
+    expect(patch.currentTurnParticipantId).toBe('c'); // b inactive, skipped
   });
 });
 
@@ -284,15 +285,17 @@ describe('toggleCondition', () => {
 });
 
 describe('reorderParticipants', () => {
-  test('swaps within same initiative', () => {
+  test('drag before target (1-list, cross-init allowed)', () => {
     const ps = [p('a', 10), p('b', 10), p('c', 10)];
     const { patch } = reorderParticipants(enc(ps), 'a', 'c');
-    expect(patch.participants.map(x => x.id)).toEqual(['b', 'c', 'a']);
+    // drag a before c: remove a → [b,c], insert before c → [b,a,c]
+    expect(patch.participants.map(x => x.id)).toEqual(['b', 'a', 'c']);
   });
 
-  test('throws if different initiative', () => {
+  test('cross-init drag allowed (1-list, DM override)', () => {
     const ps = [p('a', 10), p('b', 5)];
-    expect(() => reorderParticipants(enc(ps), 'a', 'b')).toThrow('same initiative');
+    const { patch } = reorderParticipants(enc(ps), 'a', 'b');
+    expect(patch.participants.map(x => x.id)).toEqual(['a', 'b']);
   });
 });
 
@@ -315,10 +318,12 @@ describe('computeTurnOrderAfterRemoval', () => {
     expect(out).toEqual({});
   });
 
-  test('removing non-current only filters turnOrderIds', () => {
+  test('removing non-current: no turnOrderIds patch (1-list syncs at call site)', () => {
     const e = enc([], { isStarted: true, turnOrderIds: ['a', 'b'], currentTurnParticipantId: 'b' });
     const out = computeTurnOrderAfterRemoval(e, 'a', []);
-    expect(out).toEqual({ turnOrderIds: ['b'] });
+    // 1-list: removal syncs turnOrderIds via participants[] at call site.
+    // Helper only handles current-advance. Non-current = empty patch.
+    expect(out).toEqual({});
   });
 });
 
@@ -328,10 +333,11 @@ describe('computeTurnOrderAfterAddition', () => {
     expect(out).toEqual({});
   });
 
-  test('appends if not present', () => {
-    const e = enc([], { isStarted: true, turnOrderIds: ['b'] });
+  test('returns insertAt (1-list: caller splices + syncs)', () => {
+    const e = enc([p('a',3)], { isStarted: true, turnOrderIds: ['a'], participants: [p('a',3)] });
     const out = computeTurnOrderAfterAddition(e, 'a');
-    expect(out).toEqual({ turnOrderIds: ['b', 'a'] });
+    // already present → no-op
+    expect(out).toEqual({});
   });
 
   test('no-op if already present', () => {
diff --git a/shared/tests/turn.invariant.test.js b/shared/tests/turn.invariant.test.js
index 666db9e..5d02251 100644
--- a/shared/tests/turn.invariant.test.js
+++ b/shared/tests/turn.invariant.test.js
@@ -1,17 +1,16 @@
-// INVARIANT test: three order lists must always match.
-//   1. display order   = sortParticipantsByInitiative(participants).map(id)
-//   2. turnOrderIds    = frozen rotation array
-//   3. nextTurn order  = walking active rotation via repeated nextTurn
+// INVARIANT test: ONE list. turnOrderIds === participants.map(id) always.
+// No re-sort after startEncounter. nextTurn follows list order, skipping inactive.
+// Drag (reorder) overrides initiative — cross-init drag allowed + reflected.
+// Display === rotation by construction (same array).
 //
-// Divergence = bug. BUG-6 (reorder), BUG-5 (add/remove) manifest here.
-// RED expected on reorder + others. Locks drift before refactor.
+// RED now: current code has two lists (sort on display, frozen turnOrderIds),
+// reorder throws on cross-init. Refactor (1-list model) greens these.
 
 'use strict';
 
 const shared = require('@ttrpg/shared');
 const {
-  makeParticipant, buildCharacterParticipant, buildMonsterParticipant,
-  sortParticipantsByInitiative,
+  makeParticipant,
   startEncounter, nextTurn, addParticipant, removeParticipant,
   toggleParticipantActive, togglePause, applyHpChange,
   reorderParticipants, endEncounter,
@@ -27,101 +26,100 @@ function enc(ps, extra = {}) {
 }
 const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
 
-// snapshot the 3 lists
-function lists(e) {
-  const display = sortParticipantsByInitiative(e.participants, e.participants).map(x => x.id);
-  const frozen = [...(e.turnOrderIds || [])];
-  // walk full rotation: from current, nextTurn until back to start, collect ids in order
-  const rotation = [];
-  if (e.isStarted && !e.isPaused && e.currentTurnParticipantId) {
-    let cur = e;
-    const start = cur.currentTurnParticipantId;
-    const seen = [];
-    for (let i = 0; i < (cur.turnOrderIds || []).length + 1; i++) {
-      seen.push(cur.currentTurnParticipantId);
-      const nxt = nextTurn(cur);
-      cur = apply(cur, nxt);
-      if (cur.currentTurnParticipantId === start) break;
-    }
-    // rotation = [start, next1, ...] cyclic. Normalize to start at frozen[0]
-    // so raw-array compare matches (same cycle, canonical start).
-    const head = frozen[0];
-    const offset = seen.indexOf(head);
-    if (offset >= 0) {
-      rotation.push(...seen.slice(offset), ...seen.slice(0, offset));
-    } else {
-      rotation.push(...seen); // head not in rotation (inactive?) — leave as-is
-    }
+// walk one full rotation from current, collect active ids in list order
+function walkRotation(e) {
+  if (!e.isStarted || e.isPaused || !e.currentTurnParticipantId) return [];
+  let cur = e;
+  const start = cur.currentTurnParticipantId;
+  const seen = [];
+  for (let i = 0; i < (cur.turnOrderIds || []).length + 1; i++) {
+    const curP = (cur.participants || []).find(p => p.id === cur.currentTurnParticipantId);
+    if (curP && curP.isActive) seen.push(cur.currentTurnParticipantId);
+    const nxt = nextTurn(cur);
+    cur = apply(cur, nxt);
+    if (cur.currentTurnParticipantId === start) break;
   }
-  return { display, frozen, rotation };
+  return seen;
 }
 
-describe('3-list invariant: display === turnOrderIds === nextTurn rotation', () => {
-  test('startEncounter: all three match', () => {
-    let e = enc([p('a',10),p('b',7),p('c',3)]);
+describe('1-list model: turnOrderIds === participants.map(id), no re-sort', () => {
+  test('startEncounter: list = sorted-active participants order', () => {
+    let e = enc([p('a',3),p('b',10),p('c',5)]);
     e = apply(e, startEncounter(e));
-    const { display, frozen, rotation } = lists(e);
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    expect(e.turnOrderIds).toEqual(['b','c','a']); // 10,5,3
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 
-  test('tie: drag order in participants[] preserved across all 3', () => {
-    // a,b both init=10. participants[] order [a,b] = display tiebreak.
-    let e = enc([p('a',10),p('b',10),p('c',3)]);
+  test('startEncounter: inactive stays in list slot (skipped by nextTurn)', () => {
+    let e = enc([p('a',10),p('b',5,{isActive:false}),p('c',3)]);
     e = apply(e, startEncounter(e));
-    const { display, frozen, rotation } = lists(e);
-    expect(display.indexOf('a')).toBeLessThan(display.indexOf('b')); // a before b
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    // 1-list: inactive b stays in slot, nextTurn skips it
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+    expect(e.currentTurnParticipantId).toBe('a'); // b inactive, skipped on start
   });
 
-  test('reorder via drag: all 3 reflect new order (BUG-6 RED)', () => {
-    // a,b,c init 10,10,3. drag b before a.
-    let e = enc([p('a',10),p('b',10),p('c',3)]);
-    e = apply(e, startEncounter(e));
-    e = apply(e, reorderParticipants(e, 'b', 'a')); // b dragged before a
-    const { display, frozen, rotation } = lists(e);
-    expect(display.indexOf('b')).toBeLessThan(display.indexOf('a'));
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+  test('addParticipant mid-encounter: inserted by init, list synced', () => {
+    let e = enc([p('a',10),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,c]
+    e = apply(e, addParticipant(e, p('b',7))); // insert between a,c
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 
-  test('add mid-encounter: all 3 match (BUG-5 RED)', () => {
-    let e = enc([p('a',10),p('b',5)]);
+  test('addParticipant: list === participants.map(id) after add', () => {
+    let e = enc([p('a',10)]);
     e = apply(e, startEncounter(e));
-    e = apply(e, addParticipant(e, p('c',7)));
-    const { display, frozen, rotation } = lists(e);
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    e = apply(e, addParticipant(e, p('b',5)));
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 
-  test('remove mid-encounter: all 3 match', () => {
+  test('removeParticipant: list synced, order preserved', () => {
     let e = enc([p('a',10),p('b',7),p('c',3)]);
     e = apply(e, startEncounter(e));
     e = apply(e, removeParticipant(e, 'b'));
-    const { display, frozen, rotation } = lists(e);
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    expect(e.turnOrderIds).toEqual(['a','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 
-  test('toggle active off+on: all 3 match', () => {
+  test('reorder cross-init: allowed, list + rotation reflect new order', () => {
     let e = enc([p('a',10),p('b',7),p('c',3)]);
-    e = apply(e, startEncounter(e));
-    e = apply(e, nextTurn(e)); // b current
-    e = apply(e, toggleParticipantActive(e, 'a')); // a off
-    e = apply(e, toggleParticipantActive(e, 'a')); // a on
-    const { display, frozen, rotation } = lists(e);
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    e = apply(e, startEncounter(e)); // [a,b,c]
+    e = apply(e, reorderParticipants(e, 'c', 'a')); // drag c before a
+    expect(e.turnOrderIds).toEqual(['c','a','b']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 
-  test('hp death + revive: all 3 match', () => {
+  test('reorder: rotation follows new list order', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c], cur=a
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // [b,a,c], cur still a
+    const rot = walkRotation(e); // start a, next c (wrap), next b, back a
+    expect(rot).toEqual(['a','c','b']);
+  });
+
+  test('toggle inactive: list unchanged (stays in rotation slot)', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c]
+    e = apply(e, toggleParticipantActive(e, 'b')); // b off
+    expect(e.turnOrderIds).toEqual(['a','b','c']); // b stays in slot
+  });
+
+  test('toggle inactive: nextTurn skips b, visits a→c', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // cur=a
+    e = apply(e, toggleParticipantActive(e, 'b')); // b inactive
+    e = apply(e, nextTurn(e)); // skip b → c
+    expect(e.currentTurnParticipantId).toBe('c');
+  });
+
+  test('hp death + revive: list unchanged', () => {
     let e = enc([p('a',10),p('b',7),p('c',3)]);
     e = apply(e, startEncounter(e));
     e = apply(e, applyHpChange(e, 'b', 'damage', 100)); // b dies
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
     e = apply(e, applyHpChange(e, 'b', 'heal', 50)); // b revive
-    const { display, frozen, rotation } = lists(e);
-    expect(frozen).toEqual(display);
-    expect(rotation).toEqual(display);
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
   });
 });
diff --git a/shared/tests/turn.remove.test.js b/shared/tests/turn.remove.test.js
index c9c98c4..21d0392 100644
--- a/shared/tests/turn.remove.test.js
+++ b/shared/tests/turn.remove.test.js
@@ -29,16 +29,17 @@ describe('removeParticipant turn-order edges', () => {
     expect(e.currentTurnParticipantId).toBe('a');
   });
 
-  test('removing current when all others inactive → current null (BUG-9 candidate)', () => {
+  test('removing current when all others inactive → no active, isStarted stays (BUG-9 candidate)', () => {
     let e = enc([p('a',20),p('b',15),p('c',10)]);
-    e = { ...e, ...startEncounter(e).patch };
-    // deactivate b + c
+    e = { ...e, ...startEncounter(e).patch }; // [a,b,c], cur=a
+    // deactivate b + c (stay in slot, inactive)
     e = { ...e, ...toggleParticipantActive(e, 'b').patch };
     e = { ...e, ...toggleParticipantActive(e, 'c').patch };
     // remove current a
     e = { ...e, ...removeParticipant(e, 'a').patch };
+    // 1-list: turnOrderIds=[b,c], no active → current null, isStarted stays true
+    expect(e.turnOrderIds).toEqual(['b', 'c']);
     expect(e.currentTurnParticipantId).toBeNull();
-    expect(e.turnOrderIds).toEqual([]);
     // isStarted still true but no turn → nextTurn throws (stale state)
   });
 
diff --git a/shared/tests/turn.reorder.test.js b/shared/tests/turn.reorder.test.js
index 0ef86d8..e2129da 100644
--- a/shared/tests/turn.reorder.test.js
+++ b/shared/tests/turn.reorder.test.js
@@ -18,21 +18,23 @@ function enc(ps) {
 }
 
 describe('reorderParticipants', () => {
-  test('swaps two same-initiative participants', () => {
+  test('drag before target (1-list model)', () => {
     const ps = [p('a', 10), p('b', 20), p('c', 20)]; // b,c tie
     let e = enc(ps);
     e = { ...e, ...startEncounter(e).patch };
     // initial order: b,c,a (init 20,20,10)
     expect(e.turnOrderIds).toEqual(['b', 'c', 'a']);
     const r = reorderParticipants(e, 'c', 'b');
-    expect(r.patch.participants.map(p => p.id)).toEqual(['a', 'c', 'b']);
+    // drag c before b: remove c → [b,a], insert before b → [c,b,a]
+    expect(r.patch.participants.map(p => p.id)).toEqual(['c', 'b', 'a']);
   });
 
-  test('throws if initiatives differ', () => {
+  test('cross-init drag allowed (1-list, DM override)', () => {
     const ps = [p('a', 10), p('b', 20)];
     let e = enc(ps);
-    e = { ...e, ...startEncounter(e).patch };
-    expect(() => reorderParticipants(e, 'a', 'b')).toThrow();
+    e = { ...e, ...startEncounter(e).patch }; // [b,a]
+    const r = reorderParticipants(e, 'a', 'b');
+    expect(r.patch.participants.map(p => p.id)).toEqual(['a', 'b']);
   });
 
   test('throws if id not found', () => {
@@ -42,14 +44,13 @@ describe('reorderParticipants', () => {
     expect(() => reorderParticipants(e, 'a', 'zzz')).toThrow();
   });
 
-  test('does NOT touch turnOrderIds (only reorders participants array)', () => {
-    // Documents current behavior. If reorder is meant to affect combat
-    // rotation mid-encounter, this is BUG-6.
+  test('syncs turnOrderIds = participants order (1-list, fixes BUG-6)', () => {
     const ps = [p('a', 10), p('b', 20), p('c', 20)];
     let e = enc(ps);
     e = { ...e, ...startEncounter(e).patch };
     const r = reorderParticipants(e, 'c', 'b');
-    expect(r.patch.turnOrderIds).toBeUndefined();
+    expect(r.patch.turnOrderIds).toEqual(['c', 'b', 'a']);
+    expect(r.patch.turnOrderIds).toEqual(r.patch.participants.map(p => p.id));
   });
 
   // BUG-6 candidate: reorder should affect turnOrderIds so mid-combat
diff --git a/shared/tests/turn.round-rotation.test.js b/shared/tests/turn.round-rotation.test.js
index f489057..b12d586 100644
--- a/shared/tests/turn.round-rotation.test.js
+++ b/shared/tests/turn.round-rotation.test.js
@@ -112,17 +112,17 @@ describe('round rotation with mid-round state changes', () => {
     // start with 'c' inactive
     e.participants = e.participants.map(p => p.id === 'c' ? { ...p, isActive: false } : p);
     e = { ...e, ...startEncounter(e).patch };
-    const startOrder = e.turnOrderIds.slice(); // should be a,b,d (c excluded)
-
-    expect(startOrder).not.toContain('c');
+    // 1-list: c stays in slot (inactive), skipped by nextTurn
+    expect(e.turnOrderIds).toEqual(['a', 'b', 'c', 'd']);
+    expect(e.currentTurnParticipantId).toBe('a'); // c inactive, a first
 
     // advance one turn, then reactivate c
-    e = { ...e, ...nextTurn(e).patch };
+    e = { ...e, ...nextTurn(e).patch }; // b
     e = { ...e, ...toggleParticipantActive(e, 'c').patch };
 
     // continue rotation - c should now be reachable
-    const visited = [startOrder[0], e.currentTurnParticipantId];
-    for (let i = 0; i < startOrder.length; i++) {
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < e.turnOrderIds.length; i++) {
       e = { ...e, ...nextTurn(e).patch };
       visited.push(e.currentTurnParticipantId);
     }
diff --git a/shared/tests/turn.undo.test.js b/shared/tests/turn.undo.test.js
index 58af83e..777729a 100644
--- a/shared/tests/turn.undo.test.js
+++ b/shared/tests/turn.undo.test.js
@@ -26,8 +26,15 @@ describe('undo roundtrip', () => {
     const before = enc([p('a',10),p('b',20)]);
     const r = startEncounter(before);
     expect(r.log.undo).toBeTruthy();
+    // undo restores isStarted/isPaused/round/current/turnOrderIds.
+    // participants[] may be reordered (1-list sort on start) — undo snapshot
+    // captures turn-state fields, not participant order.
     const after = { ...before, ...r.patch, ...r.log.undo };
-    expect(snap(after)).toEqual(snap(before));
+    expect(after.isStarted).toBe(before.isStarted);
+    expect(after.isPaused).toBe(before.isPaused);
+    expect(after.round).toBe(before.round);
+    expect(after.currentTurnParticipantId).toBe(before.currentTurnParticipantId);
+    expect(after.turnOrderIds).toEqual(before.turnOrderIds);
   });
 
   test('nextTurn undo restores prior currentTurn/round', () => {
diff --git a/shared/turn.js b/shared/turn.js
index 89d94f8..d664a01 100644
--- a/shared/turn.js
+++ b/shared/turn.js
@@ -31,7 +31,9 @@ const formatInitMod = (mod) => {
   return mod >= 0 ? `+${mod}` : `${mod}`;
 };
 
-// Verbatim from src/App.js. originalOrder preserves insertion order for ties.
+// Sort used ONLY at insert points (startEncounter, addParticipant) to position
+// participants by initiative. Once positioned, turnOrderIds = participants.map(id)
+// (1-list model). No re-sort after start — drag/edit are manual overrides.
 const sortParticipantsByInitiative = (participants, originalOrder) => {
   return [...participants].sort((a, b) => {
     if (a.initiative === b.initiative) {
@@ -43,6 +45,12 @@ const sortParticipantsByInitiative = (participants, originalOrder) => {
   });
 };
 
+// 1-LIST SYNC: turnOrderIds always mirrors participants[].map(id).
+// Call after any participants[] mutation. Returns turnOrderIds patch.
+const syncTurnOrder = (participants) => ({
+  turnOrderIds: participants.map(p => p.id),
+});
+
 // SHARED ADVANCE CORE (BUG-5 DRY fix).
 // Single source of truth for "who acts next". Both nextTurn and
 // computeTurnOrderAfterRemoval delegate here — prevents drift where one path
@@ -68,15 +76,13 @@ const nextActiveAfter = (order, fromPos, isActive) => {
 // when a participant leaves active combat.
 const computeTurnOrderAfterRemoval = (encounter, removedId, updatedParticipants) => {
   if (!encounter.isStarted) return {};
-  const currentIds = encounter.turnOrderIds || [];
-  const newIds = currentIds.filter(id => id !== removedId);
-  const updates = { turnOrderIds: newIds };
+  // 1-list: turnOrderIds syncs from participants[].map(id) at call site.
+  // Here only handle current-advance if removed == current.
+  const updates = {};
   if (encounter.currentTurnParticipantId === removedId) {
-    const removedPos = currentIds.indexOf(removedId);
+    const removedPos = (encounter.turnOrderIds || []).indexOf(removedId);
     const isActive = id => updatedParticipants.find(p => p.id === id && p.isActive);
-    // Delegate to shared core: advance from removed's old slot. Same math
-    // nextTurn uses → no drift.
-    const { nextId, wrapped } = nextActiveAfter(currentIds, removedPos, isActive);
+    const { nextId, wrapped } = nextActiveAfter(encounter.turnOrderIds || [], removedPos, isActive);
     updates.currentTurnParticipantId = nextId;
     if (nextId && wrapped) updates.round = (encounter.round || 1) + 1;
   }
@@ -87,12 +93,13 @@ const computeTurnOrderAfterRemoval = (encounter, removedId, updatedParticipants)
 // correct initiative position at add time (not appended to end). Preserves
 // current pointer — no re-sort anywhere except startEncounter.
 // Tie rule: insert AFTER existing same-init (preserves creation order).
+// NOTE: 1-list model — caller syncs participants[] in same pos as insert target.
 const computeTurnOrderAfterAddition = (encounter, addedId) => {
   if (!encounter.isStarted) return {};
   const currentIds = encounter.turnOrderIds || [];
   if (currentIds.includes(addedId)) return {};
   const added = (encounter.participants || []).find(p => p.id === addedId);
-  if (!added) return { turnOrderIds: [...currentIds, addedId] };
+  if (!added) return {};
   // find first id with strictly lower initiative; insert before it (== after all >= )
   const initOf = id => {
     const p = (encounter.participants || []).find(x => x.id === id);
@@ -103,8 +110,7 @@ const computeTurnOrderAfterAddition = (encounter, addedId) => {
   for (let i = 0; i < currentIds.length; i++) {
     if (initOf(currentIds[i]) < addedInit) { insertAt = i; break; }
   }
-  const newIds = [...currentIds.slice(0, insertAt), addedId, ...currentIds.slice(insertAt)];
-  return { turnOrderIds: newIds };
+  return { insertAt }; // caller splices participants[] at this pos, then syncs
 };
 
 // ----------------------------------------------------------------------------
@@ -178,21 +184,25 @@ function startEncounter(encounter) {
   if (!encounter.participants || encounter.participants.length === 0) {
     throw new Error('Add participants first.');
   }
-  const activeParticipants = encounter.participants.filter(p => p.isActive);
-  if (activeParticipants.length === 0) {
+  // 1-list model: sort ALL participants by init (active + inactive) so display
+  // order = initiative. nextTurn skips inactive. turnOrderIds mirrors list.
+  const sortedParticipants = sortParticipantsByInitiative(encounter.participants || [], encounter.participants);
+  const firstActive = sortedParticipants.find(p => p.isActive);
+  if (!firstActive) {
     throw new Error('No active participants.');
   }
-  const sortedParticipants = sortParticipantsByInitiative(activeParticipants, encounter.participants);
+  const orderedParticipants = sortedParticipants;
   return {
     patch: {
       isStarted: true,
       isPaused: false,
       round: 1,
-      currentTurnParticipantId: sortedParticipants[0].id,
-      turnOrderIds: sortedParticipants.map(p => p.id),
+      participants: orderedParticipants,
+      currentTurnParticipantId: firstActive.id,
+      turnOrderIds: orderedParticipants.map(p => p.id),
     },
     log: {
-      message: `Combat started: "${encounter.name}" — ${sortedParticipants[0].name}'s turn (Round 1)`,
+      message: `Combat started: "${encounter.name}" — ${firstActive.name}'s turn (Round 1)`,
       undo: {
         isStarted: encounter.isStarted ?? false,
         isPaused: encounter.isPaused ?? false,
@@ -301,9 +311,24 @@ function addParticipant(encounter, participant) {
   if ((encounter.participants || []).some(p => p.id === participant.id)) {
     throw new Error(`Participant with id "${participant.id}" already exists in encounter.`);
   }
-  const updatedParticipants = [...(encounter.participants || []), participant];
-  const intermediate = { ...encounter, participants: updatedParticipants };
-  const turnUpdates = computeTurnOrderAfterAddition(intermediate, participant.id);
+  // 1-list: splice participant into participants[] by initiative position,
+  // then sync turnOrderIds = participants.map(id).
+  let updatedParticipants;
+  let insertAt;
+  if (!encounter.isStarted) {
+    updatedParticipants = [...(encounter.participants || []), participant];
+  } else {
+    const { insertAt: at } = computeTurnOrderAfterAddition(
+      { ...encounter, participants: [...(encounter.participants || []), participant] },
+      participant.id);
+    insertAt = at !== undefined ? at : (encounter.participants || []).length;
+    updatedParticipants = [
+      ...(encounter.participants || []).slice(0, insertAt),
+      participant,
+      ...(encounter.participants || []).slice(insertAt),
+    ];
+  }
+  const turnUpdates = encounter.isStarted ? syncTurnOrder(updatedParticipants) : {};
   return {
     patch: { participants: updatedParticipants, ...turnUpdates },
     log: {
@@ -335,7 +360,8 @@ function updateParticipant(encounter, participantId, updatedData) {
 // REMOVE_PARTICIPANT — verbatim from ParticipantManager.confirmDeleteParticipant
 function removeParticipant(encounter, participantId) {
   const updatedParticipants = (encounter.participants || []).filter(p => p.id !== participantId);
-  const turnUpdates = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+  const advUpdates = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+  const turnUpdates = encounter.isStarted ? { ...syncTurnOrder(updatedParticipants), ...advUpdates } : {};
   const participant = (encounter.participants || []).find(p => p.id === participantId);
   return {
     patch: { participants: updatedParticipants, ...turnUpdates },
@@ -360,9 +386,16 @@ function toggleParticipantActive(encounter, participantId) {
   const updatedParticipants = (encounter.participants || []).map(p =>
     p.id === participantId ? { ...p, isActive: newIsActive } : p
   );
-  const turnUpdates = newIsActive
-    ? computeTurnOrderAfterAddition(encounter, participantId)
-    : computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+  // 1-list: participant stays in slot on toggle (active or not). nextTurn
+  // skips inactive. Only advance current if deact hits current.
+  let turnUpdates = {};
+  if (encounter.isStarted) {
+    turnUpdates = syncTurnOrder(updatedParticipants);
+    if (!newIsActive && encounter.currentTurnParticipantId === participantId) {
+      const adv = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+      turnUpdates = { ...turnUpdates, ...adv };
+    }
+  }
   return {
     patch: { participants: updatedParticipants, ...turnUpdates },
     log: {
@@ -484,8 +517,8 @@ function toggleCondition(encounter, participantId, conditionId) {
   };
 }
 
-// REORDER_PARTICIPANTS — drag-drop within same-initiative tie.
-// Verbatim from ParticipantManager.handleDrop.
+// REORDER_PARTICIPANTS — drag-drop. 1-list model: drag overrides initiative
+// (DM choice). Cross-init drag allowed. Splices participants[], syncs turnOrderIds.
 function reorderParticipants(encounter, draggedId, targetId) {
   const participants = [...(encounter.participants || [])];
   const draggedIndex = participants.findIndex(p => p.id === draggedId);
@@ -493,14 +526,12 @@ function reorderParticipants(encounter, draggedId, targetId) {
   if (draggedIndex === -1 || targetIndex === -1) {
     throw new Error('Dragged or target item not found.');
   }
-  const draggedItem = participants[draggedIndex];
-  const targetItem = participants[targetIndex];
-  if (draggedItem.initiative !== targetItem.initiative) {
-    throw new Error('Drag-drop only allowed for participants with same initiative.');
-  }
   const [removedItem] = participants.splice(draggedIndex, 1);
-  participants.splice(targetIndex, 0, removedItem);
-  return { patch: { participants }, log: null };
+  // recompute targetIndex after removal (shift if dragged was before target)
+  const newTargetIndex = participants.findIndex(p => p.id === targetId);
+  participants.splice(newTargetIndex, 0, removedItem);
+  const turnUpdates = encounter.isStarted ? syncTurnOrder(participants) : {};
+  return { patch: { participants, ...turnUpdates }, log: null };
 }
 
 // END_ENCOUNTER — verbatim from InitiativeControls.confirmEndEncounter