diff --git a/core/src/Boss.cpp b/core/src/Boss.cpp
index 6790e7d..4bc757d 100644
--- a/core/src/Boss.cpp
+++ b/core/src/Boss.cpp
@@ -314,3 +314,161 @@ int DragonFight::resolvePlayerShot(const DragonPlayerInput& input) {
     return 1;
 }
 
+void DragonFight::applyPlayerMelee(const DragonPlayerInput& input) {
+    if (!input.present || input.meleeDamage <= 0.0f || !boss.alive) return;
+    if (distanceBetween(boss.position, input.position) > cfg.meleeReach) return;
+
+    float factor = boss.phase == BossPhase::Perching ? 1.0f : cfg.flyingDamageFactor;
+    float dealt = std::min(input.meleeDamage * factor, boss.health);
+    boss.health -= dealt;
+    boss.damageTaken += dealt;
+}
+
+float DragonFight::applyCrystalHealing() {
+    if (boss.health <= 0.0f) return 0.0f;
+
+    float healed = 0.0f;
+    for (const CrystalNode& crystal : pillarCrystals) {
+        if (!crystal.alive) continue;
+        if (distanceBetween(crystalCenter(crystal.position), boss.position) > cfg.crystalHealRange)
+            continue;
+        float room = boss.maxHealth - boss.health - healed;
+        if (room <= 0.0f) break;
+        healed += std::min(cfg.crystalHealPerTick, room);
+    }
+    boss.health += healed;
+    boss.healingReceived += healed;
+    return healed;
+}
+
+BossTickReport DragonFight::tick(const DragonPlayerInput& input) {
+    BossTickReport report;
+    report.previousPhase = boss.phase;
+    report.phase = boss.phase;
+    report.bossHealth = boss.health;
+
+    if (boss.phase == BossPhase::Defeated) {
+        report.defeated = true;
+        return report;
+    }
+
+    lastInput = input;
+    damageThisTick = 0.0f;
+
+    int crystalsKilled = resolvePlayerShot(input);
+    applyPlayerMelee(input);
+    float healed = applyCrystalHealing();
+
+    bool lastCrystalDown = crystalsKilled > 0 && aliveCrystalCount() == 0;
+    bool lethalBlow = boss.health <= 0.0f && boss.phase != BossPhase::Dying;
+    if (lastCrystalDown || lethalBlow) tree.reset();
+
+    ctx.playerPresent = input.present;
+    ctx.playerPosition = input.position;
+
+    ++boss.phaseTicks;
+    int changesBefore = boss.phaseChanges;
+    tree.tick(ctx);
+    boss.tick = ctx.tick;
+    if (boss.phase != BossPhase::Defeated) boss.bar.setFromHealth(boss.health, boss.maxHealth);
+
+    report.phase = boss.phase;
+    report.phaseChanged = boss.phaseChanges != changesBefore;
+    report.bossHealth = boss.health;
+    report.healedThisTick = healed;
+    report.damageToTargets = damageThisTick;
+    report.crystalsDestroyed = crystalsKilled;
+    report.defeated = boss.phase == BossPhase::Defeated;
+    return report;
+}
+
+bool DragonFight::placeVictoryStructures(World& world, const EndGenerator& end) const {
+    if (!portalOpen) return false;
+    end.placeExitPortal(world);
+    return true;
+}
+
+Block witherBaseBlock() { return Block::SoulSand; }
+Block witherHeadBlock() { return Block::Pumpkin; }
+
+bool witherPatternAt(const World& world, const Vec3i& baseCell, bool alongX) {
+    if (world.blockAt(baseCell.x, baseCell.y, baseCell.z) != witherBaseBlock()) return false;
+    for (int along = -1; along <= 1; ++along) {
+        Vec3i arm = witherOffset(baseCell, along, 1, alongX);
+        if (world.blockAt(arm.x, arm.y, arm.z) != witherBaseBlock()) return false;
+        Vec3i head = witherOffset(baseCell, along, 2, alongX);
+        if (world.blockAt(head.x, head.y, head.z) != witherHeadBlock()) return false;
+    }
+    return true;
+}
+
+bool findWitherPattern(const World& world, const Vec3i& baseCell, bool& outAlongX) {
+    if (witherPatternAt(world, baseCell, true)) {
+        outAlongX = true;
+        return true;
+    }
+    if (witherPatternAt(world, baseCell, false)) {
+        outAlongX = false;
+        return true;
+    }
+    return false;
+}
+
+void consumeWitherPattern(World& world, const Vec3i& baseCell, bool alongX) {
+    world.setBlock(baseCell.x, baseCell.y, baseCell.z, Block::Air);
+    for (int along = -1; along <= 1; ++along) {
+        Vec3i arm = witherOffset(baseCell, along, 1, alongX);
+        world.setBlock(arm.x, arm.y, arm.z, Block::Air);
+        Vec3i head = witherOffset(baseCell, along, 2, alongX);
+        world.setBlock(head.x, head.y, head.z, Block::Air);
+    }
+}
+
+WitherFight::WitherFight(uint32_t seed, const WitherFightConfig& config) : cfg(config) {
+    boss.kind = BossKind::Wither;
+    boss.maxHealth = cfg.maxHealth;
+    boss.health = cfg.maxHealth;
+    boss.rng = seed != 0u ? seed : 0x2f6b3ca1u;
+    boss.phase = BossPhase::Dormant;
+    boss.bar.title = "Wither";
+    boss.bar.color = BossBarColor::Purple;
+    boss.bar.style = BossBarStyle::Notched6;
+    boss.bar.visible = false;
+    ctx.rng = boss.rng;
+    buildTree();
+}
+
+int WitherFight::aliveMinionCount() const {
+    int total = 0;
+    for (const BossMinion& minion : summoned) {
+        if (minion.alive) ++total;
+    }
+    return total;
+}
+
+int WitherFight::nearestAliveTarget() const {
+    if (activeTargets == nullptr) return -1;
+    int best = -1;
+    float bestSpan = 0.0f;
+    for (std::size_t i = 0; i < activeTargets->size(); ++i) {
+        const WitherTarget& candidate = (*activeTargets)[i];
+        if (!candidate.alive) continue;
+        float span = distanceBetween(boss.position, candidate.position);
+        if (best >= 0 && span >= bestSpan) continue;
+        best = static_cast<int>(i);
+        bestSpan = span;
+    }
+    return best;
+}
+
+void WitherFight::buildTree() {
+    auto defeat = seq("defeat");
+    defeat->add(cond("healthGone", [this](BehaviorContext&) { return boss.health <= 0.0f; }));
+    defeat->add(act("collapse", [this](BehaviorContext&) {
+        boss.enterPhase(BossPhase::Defeated);
+        boss.alive = false;
+        boss.bar.visible = false;
+        boss.bar.setFromHealth(0.0f, boss.maxHealth);
+        return BehaviorStatus::Success;
+    }));
+