diff --git a/combat/combat_test.go b/combat/combat_test.go
index 388c1af..ee9c47a 100644
--- a/combat/combat_test.go
+++ b/combat/combat_test.go
@@ -76,3 +76,63 @@ func TestFleeChance(t *testing.T) {
 		t.Errorf("Flee success rate suspicious: %d/100", successes)
 	}
 }
+
+func TestMonsterAIBossAoE(t *testing.T) {
+	boss := &entity.Monster{Name: "Boss", HP: 100, IsBoss: true}
+	players := []*entity.Player{entity.NewPlayer("P1", entity.ClassWarrior)}
+
+	// Turn 0 should NOT AoE
+	_, isAoE := MonsterAI(boss, players, 0)
+	if isAoE {
+		t.Error("boss should not AoE on turn 0")
+	}
+	// Turn 3 should AoE
+	_, isAoE = MonsterAI(boss, players, 3)
+	if !isAoE {
+		t.Error("boss should AoE on turn 3")
+	}
+	// Turn 6 should AoE
+	_, isAoE = MonsterAI(boss, players, 6)
+	if !isAoE {
+		t.Error("boss should AoE on turn 6")
+	}
+}
+
+func TestMonsterAILowestHP(t *testing.T) {
+	p1 := entity.NewPlayer("Tank", entity.ClassWarrior) // 120 HP
+	p2 := entity.NewPlayer("Mage", entity.ClassMage)     // 70 HP
+	p2.HP = 10                                            // very low
+
+	// Run many times — at least some should target p2 (30% chance)
+	targetedLow := 0
+	for i := 0; i < 100; i++ {
+		m := &entity.Monster{Name: "Orc", HP: 50}
+		idx, _ := MonsterAI(m, []*entity.Player{p1, p2}, 1)
+		if idx == 1 {
+			targetedLow++
+		}
+	}
+	// Should target low HP player roughly 30% of time
+	if targetedLow < 10 || targetedLow > 60 {
+		t.Errorf("lowest HP targeting out of expected range: %d/100", targetedLow)
+	}
+}
+
+func TestCalcDamageWithMultiplier(t *testing.T) {
+	// AoE multiplier 0.8: ATK=20, DEF=5, mult=0.8 → base = 20*0.8 - 5 = 11
+	// Range: 11 * 0.85 to 11 * 1.15 = ~9.35 to ~12.65
+	for i := 0; i < 50; i++ {
+		dmg := CalcDamage(20, 5, 0.8)
+		if dmg < 9 || dmg > 13 {
+			t.Errorf("AoE damage %d out of expected range 9-13", dmg)
+		}
+	}
+}
+
+func TestCalcDamageHighDEF(t *testing.T) {
+	// When DEF > ATK*mult, should deal minimum 1 damage
+	dmg := CalcDamage(5, 100, 1.0)
+	if dmg != 1 {
+		t.Errorf("expected minimum damage 1, got %d", dmg)
+	}
+}
diff --git a/entity/monster_test.go b/entity/monster_test.go
index c9f6c30..604cd7c 100644
--- a/entity/monster_test.go
+++ b/entity/monster_test.go
@@ -36,3 +36,23 @@ func TestMonsterDEFScaling(t *testing.T) {
 		t.Errorf("Boss5 DEF should be base 8, got %d", boss.DEF)
 	}
 }
+
+func TestTickTaunt(t *testing.T) {
+	m := &Monster{Name: "Orc", HP: 50, TauntTarget: true, TauntTurns: 2}
+	m.TickTaunt()
+	if m.TauntTurns != 1 || !m.TauntTarget {
+		t.Error("should still be taunted with 1 turn left")
+	}
+	m.TickTaunt()
+	if m.TauntTurns != 0 || m.TauntTarget {
+		t.Error("taunt should be cleared at 0")
+	}
+}
+
+func TestMonsterAtMinFloor(t *testing.T) {
+	// Slime at floor 1 (minFloor=1) should have base stats
+	m := NewMonster(MonsterSlime, 1)
+	if m.HP != 20 || m.ATK != 5 || m.DEF != 1 {
+		t.Errorf("Slime at min floor should be base stats, got HP=%d ATK=%d DEF=%d", m.HP, m.ATK, m.DEF)
+	}
+}
diff --git a/entity/player_test.go b/entity/player_test.go
index 35e504e..6b55cfe 100644
--- a/entity/player_test.go
+++ b/entity/player_test.go
@@ -63,3 +63,130 @@ func TestPlayerTakeDamage(t *testing.T) {
 		t.Error("Player should be dead")
 	}
 }
+
+func TestIsOut(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior)
+	if p.IsOut() {
+		t.Error("alive player should not be out")
+	}
+	p.Dead = true
+	if !p.IsOut() {
+		t.Error("dead player should be out")
+	}
+	p.Dead = false
+	p.Fled = true
+	if !p.IsOut() {
+		t.Error("fled player should be out")
+	}
+}
+
+func TestRevive(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior) // 120 MaxHP
+	p.TakeDamage(200)
+	if !p.IsDead() {
+		t.Error("should be dead")
+	}
+	p.Revive(0.30)
+	if p.IsDead() {
+		t.Error("should be alive after revive")
+	}
+	if p.HP != 36 { // 120 * 0.30
+		t.Errorf("HP should be 36, got %d", p.HP)
+	}
+}
+
+func TestHealCap(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior) // 120 HP
+	p.HP = 100
+	p.Heal(50) // should cap at 120
+	if p.HP != 120 {
+		t.Errorf("HP should cap at 120, got %d", p.HP)
+	}
+}
+
+func TestEffectiveATKWithItems(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior) // base ATK 12
+	p.Inventory = append(p.Inventory, Item{Name: "Sword", Type: ItemWeapon, Bonus: 5})
+	p.Inventory = append(p.Inventory, Item{Name: "Sword2", Type: ItemWeapon, Bonus: 3})
+	if p.EffectiveATK() != 20 { // 12 + 5 + 3
+		t.Errorf("ATK should be 20, got %d", p.EffectiveATK())
+	}
+}
+
+func TestEffectiveDEFWithItems(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior) // base DEF 8
+	p.Inventory = append(p.Inventory, Item{Name: "Shield", Type: ItemArmor, Bonus: 4})
+	if p.EffectiveDEF() != 12 { // 8 + 4
+		t.Errorf("DEF should be 12, got %d", p.EffectiveDEF())
+	}
+}
+
+func TestStatusEffectPoison(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior) // 120 HP
+	p.AddEffect(ActiveEffect{Type: StatusPoison, Duration: 2, Value: 10})
+	if !p.HasEffect(StatusPoison) {
+		t.Error("should have poison")
+	}
+	msgs := p.TickEffects()
+	if len(msgs) != 1 {
+		t.Errorf("expected 1 message, got %d", len(msgs))
+	}
+	if p.HP != 110 {
+		t.Errorf("HP should be 110 after poison tick, got %d", p.HP)
+	}
+	// Poison can't kill
+	p.HP = 5
+	p.TickEffects() // duration expires after this tick
+	if p.HP != 1 {
+		t.Errorf("poison should leave at 1 HP, got %d", p.HP)
+	}
+	if p.IsDead() {
+		t.Error("poison should not kill")
+	}
+	if p.HasEffect(StatusPoison) {
+		t.Error("poison should have expired")
+	}
+}
+
+func TestStatusEffectBurn(t *testing.T) {
+	p := NewPlayer("test", ClassMage) // 70 HP
+	p.AddEffect(ActiveEffect{Type: StatusBurn, Duration: 1, Value: 100})
+	p.TickEffects()
+	if !p.IsDead() {
+		t.Error("burn should be able to kill")
+	}
+}
+
+func TestRelicPoisonImmunity(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior)
+	p.Relics = append(p.Relics, Relic{Name: "Antidote", Effect: RelicPoisonImmunity})
+	p.AddEffect(ActiveEffect{Type: StatusPoison, Duration: 3, Value: 10})
+	if p.HasEffect(StatusPoison) {
+		t.Error("should be immune to poison")
+	}
+}
+
+func TestRelicBurnResist(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior)
+	p.Relics = append(p.Relics, Relic{Name: "Flame Guard", Effect: RelicBurnResist})
+	p.AddEffect(ActiveEffect{Type: StatusBurn, Duration: 2, Value: 10})
+	// Burn value should be halved to 5
+	if len(p.Effects) == 0 {
+		t.Fatal("should have burn effect (resisted, not immune)")
+	}
+	if p.Effects[0].Value != 5 {
+		t.Errorf("burn value should be halved to 5, got %d", p.Effects[0].Value)
+	}
+}
+
+func TestEffectOverwrite(t *testing.T) {
+	p := NewPlayer("test", ClassWarrior)
+	p.AddEffect(ActiveEffect{Type: StatusPoison, Duration: 1, Value: 5})
+	p.AddEffect(ActiveEffect{Type: StatusPoison, Duration: 3, Value: 10}) // should overwrite
+	if len(p.Effects) != 1 {
+		t.Errorf("should have 1 effect, got %d", len(p.Effects))
+	}
+	if p.Effects[0].Duration != 3 || p.Effects[0].Value != 10 {
+		t.Error("should have overwritten with new values")
+	}
+}