Fix Emperor of Bones

crates/engine/src/game/effects/mod.rs

@@ -11205,6 +11205,13 @@ fn resolve_chain_body(
                 );
                 resolve_ability_chain(state, &trailing_resolved, events, depth + 1)?;
             }
+        } else if ability.forward_result && forwarded_objects.is_empty() {
+            // CR 608.2c: A forward-result continuation is anchored to the object
+            // moved by the preceding instruction. If no object moved, that
+            // instruction has no referent for dependent riders such as "it gains
+            // haste" or "sacrifice it"; do not let ParentTarget fall back to the
+            // original ability source.
+            return Ok(());
         } else if !forwarded_objects.is_empty() {
             let mut sub_with_context = sub.as_ref().clone();
             // CR 707.10: `CopySpell { SelfRef }` copies the resolving spell

crates/engine/tests/integration/issue_1515_emperor_of_bones.rs

@@ -236,6 +236,92 @@ fn emperor_of_bones_counter_trigger_uses_returned_creature_in_cast_pipeline() {
     );
 }
 
+#[test]
+fn emperor_of_bones_adapt_pipeline_binds_delayed_sacrifice_to_returned_creature() {
+    let mut scenario = GameScenario::new();
+    scenario.at_phase(Phase::PreCombatMain);
+    let emperor = scenario
+        .add_creature_from_oracle(P0, "Emperor of Bones", 2, 2, EMPEROR_ORACLE)
+        .id();
+    let returned = scenario
+        .add_creature_to_exile(P0, "Linked Gravebeast", 3, 3)
+        .id();
+    let swamp_a = scenario.add_basic_land(P0, engine::types::mana::ManaColor::Black);
+    let swamp_b = scenario.add_basic_land(P0, engine::types::mana::ManaColor::Black);
+
+    let mut runner = scenario.build();
+    runner.state_mut().exile_links.push(ExileLink {
+        exiled_id: returned,
+        source_id: emperor,
+        kind: ExileLinkKind::TrackedBySource,
+    });
+
+    runner
+        .activate(emperor, 0)
+        .pay_with(&[swamp_a, swamp_b])
+        .resolve();
+
+    let state = runner.state();
+    assert_eq!(
+        state.objects[&returned].zone,
+        Zone::Battlefield,
+        "Adapt must resolve Emperor's counter trigger and return the linked creature"
+    );
+    assert_eq!(
+        state.delayed_triggers.len(),
+        1,
+        "the counter trigger must install one delayed sacrifice"
+    );
+    assert_eq!(
+        state.delayed_triggers[0].ability.targets,
+        vec![engine::types::ability::TargetRef::Object(returned)],
+        "the Adapt-triggered delayed sacrifice must snapshot the returned creature"
+    );
+    assert_eq!(
+        state.objects[&emperor].zone,
+        Zone::Battlefield,
+        "Emperor must remain on the battlefield until its own ability is removed"
+    );
+}
+
+#[test]
+fn emperor_of_bones_adapt_without_linked_exile_has_no_riders_to_apply() {
+    let mut scenario = GameScenario::new();
+    scenario.at_phase(Phase::PreCombatMain);
+    let emperor = scenario
+        .add_creature_from_oracle(P0, "Emperor of Bones", 2, 2, EMPEROR_ORACLE)
+        .id();
+    let swamp_a = scenario.add_basic_land(P0, engine::types::mana::ManaColor::Black);
+    let swamp_b = scenario.add_basic_land(P0, engine::types::mana::ManaColor::Black);
+
+    let mut runner = scenario.build();
+    runner
+        .activate(emperor, 0)
+        .pay_with(&[swamp_a, swamp_b])
+        .resolve();
+
+    let state = runner.state();
+    assert_eq!(
+        state.objects[&emperor]
+            .counters
+            .get(&CounterType::Plus1Plus1)
+            .copied()
+            .unwrap_or(0),
+        2,
+        "Adapt must still put its counters on Emperor"
+    );
+    assert_eq!(
+        state.delayed_triggers.len(),
+        0,
+        "no returned creature means Emperor's haste and delayed Sacrifice riders must not run"
+    );
+    assert_eq!(
+        state.objects[&emperor].zone,
+        Zone::Battlefield,
+        "Emperor must remain on the battlefield when no linked creature was exiled"
+    );
+}
+
 /// CR 614.12a + CR 400.7j: An as-enters choice on the returned permanent must
 /// complete without losing later instructions that refer to that permanent.
 #[test]