diff --git a/src/creatures/monsters/spawns/spawn_monster.cpp b/src/creatures/monsters/spawns/spawn_monster.cpp
index ed26b34568f..0353ee49bb0 100644
--- a/src/creatures/monsters/spawns/spawn_monster.cpp
+++ b/src/creatures/monsters/spawns/spawn_monster.cpp
@@ -156,8 +156,7 @@ void SpawnMonster::startSpawnMonsterCheck() {
 }
 
 SpawnMonster::~SpawnMonster() {
-	for (const auto &it : spawnedMonsterMap) {
-		std::shared_ptr<Monster> monster = it.second;
+	for (const auto &[_, monster] : spawnedMonsterMap) {
 		monster->setSpawnMonster(nullptr);
 	}
 }
@@ -177,6 +176,9 @@ bool SpawnMonster::isInSpawnMonsterZone(const Position &pos) {
 }
 
 bool SpawnMonster::spawnMonster(uint32_t spawnMonsterId, const std::shared_ptr<MonsterType> monsterType, const Position &pos, Direction dir, bool startup /*= false*/) {
+	if (spawnedMonsterMap.contains(spawnMonsterId)) {
+		return false;
+	}
 	auto monster = std::make_shared<Monster>(monsterType);
 	if (startup) {
 		// No need to send out events to the surrounding since there is no one out there to listen!
@@ -193,14 +195,14 @@ bool SpawnMonster::spawnMonster(uint32_t spawnMonsterId, const std::shared_ptr<M
 	monster->setSpawnMonster(this);
 	monster->setMasterPos(pos);
 
-	spawnedMonsterMap.insert(spawned_pair(spawnMonsterId, monster));
+	spawnedMonsterMap[spawnMonsterId] = monster;
 	spawnMonsterMap[spawnMonsterId].lastSpawn = OTSYS_TIME();
 	g_events().eventMonsterOnSpawn(monster, pos);
 	g_callbacks().executeCallback(EventCallback_t::monsterOnSpawn, &EventCallback::monsterOnSpawn, monster, pos);
 	return true;
 }
 
-void SpawnMonster::startup() {
+void SpawnMonster::startup(bool delayed) {
 	if (g_configManager().getBoolean(RANDOM_MONSTER_SPAWN)) {
 		for (auto it = spawnMonsterMap.begin(); it != spawnMonsterMap.end(); ++it) {
 			auto &[spawnMonsterId, sb] = *it;
@@ -230,7 +232,11 @@ void SpawnMonster::startup() {
 		if (!mType) {
 			continue;
 		}
-		spawnMonster(spawnMonsterId, mType, sb.pos, sb.direction, true);
+		if (delayed) {
+			g_dispatcher().addEvent(std::bind(&SpawnMonster::scheduleSpawn, this, spawnMonsterId, sb, mType, 0), "SpawnMonster::startup");
+		} else {
+			scheduleSpawn(spawnMonsterId, sb, mType, 0);
+		}
 	}
 }
 
@@ -243,13 +249,11 @@ void SpawnMonster::checkSpawnMonster() {
 	cleanup();
 	uint32_t spawnMonsterCount = 0;
 
-	for (auto &it : spawnMonsterMap) {
-		uint32_t spawnMonsterId = it.first;
-		if (spawnedMonsterMap.find(spawnMonsterId) != spawnedMonsterMap.end()) {
+	for (auto &[spawnMonsterId, sb] : spawnMonsterMap) {
+		if (spawnedMonsterMap.contains(spawnMonsterId)) {
 			continue;
 		}
 
-		spawnBlock_t &sb = it.second;
 		const auto &mType = sb.getMonsterType();
 		if (!mType) {
 			continue;
@@ -292,15 +296,15 @@ void SpawnMonster::scheduleSpawn(uint32_t spawnMonsterId, spawnBlock_t &sb, cons
 }
 
 void SpawnMonster::cleanup() {
-	auto it = spawnedMonsterMap.begin();
-	while (it != spawnedMonsterMap.end()) {
-		auto monster = it->second;
+	std::vector<uint32_t> removeList;
+	for (const auto &[spawnMonsterId, monster] : spawnedMonsterMap) {
 		if (monster == nullptr || monster->isRemoved()) {
-			it = spawnedMonsterMap.erase(it);
-		} else {
-			++it;
+			removeList.push_back(spawnMonsterId);
 		}
 	}
+	for (const auto &spawnMonsterId : removeList) {
+		spawnedMonsterMap.erase(spawnMonsterId);
+	}
 }
 
 bool SpawnMonster::addMonster(const std::string &name, const Position &pos, Direction dir, uint32_t scheduleInterval, uint32_t weight /*= 1*/) {
@@ -354,12 +358,14 @@ bool SpawnMonster::addMonster(const std::string &name, const Position &pos, Dire
 }
 
 void SpawnMonster::removeMonster(std::shared_ptr<Monster> monster) {
-	for (auto it = spawnedMonsterMap.begin(), end = spawnedMonsterMap.end(); it != end; ++it) {
-		if (it->second == monster) {
-			spawnedMonsterMap.erase(it);
+	uint32_t spawnMonsterId = 0;
+	for (const auto &[id, m] : spawnedMonsterMap) {
+		if (m == monster) {
+			spawnMonsterId = id;
 			break;
 		}
 	}
+	spawnedMonsterMap.erase(spawnMonsterId);
 }
 
 void SpawnMonster::setMonsterVariant(const std::string &variant) {
diff --git a/src/creatures/monsters/spawns/spawn_monster.hpp b/src/creatures/monsters/spawns/spawn_monster.hpp
index bf4a47b1f52..36dd2e1ca09 100644
--- a/src/creatures/monsters/spawns/spawn_monster.hpp
+++ b/src/creatures/monsters/spawns/spawn_monster.hpp
@@ -42,7 +42,7 @@ class SpawnMonster {
 	uint32_t getInterval() const {
 		return interval;
 	}
-	void startup();
+	void startup(bool delayed = false);
 
 	void startSpawnMonsterCheck();
 	void stopEvent();
@@ -58,12 +58,10 @@ class SpawnMonster {
 
 private:
 	// map of the spawned creatures
-	using SpawnedMap = std::multimap<uint32_t, std::shared_ptr<Monster>>;
-	using spawned_pair = SpawnedMap::value_type;
-	SpawnedMap spawnedMonsterMap;
+	phmap::parallel_flat_hash_map_m<uint32_t, std::shared_ptr<Monster>> spawnedMonsterMap;
 
 	// map of creatures in the spawn
-	std::map<uint32_t, spawnBlock_t> spawnMonsterMap;
+	phmap::parallel_flat_hash_map_m<uint32_t, spawnBlock_t> spawnMonsterMap;
 
 	Position centerPos;
 	int32_t radius;
diff --git a/src/game/scheduling/task.hpp b/src/game/scheduling/task.hpp
index f42602242c5..9f89a849a2c 100644
--- a/src/game/scheduling/task.hpp
+++ b/src/game/scheduling/task.hpp
@@ -100,6 +100,7 @@ class Task {
 			"Raids::checkRaids",
 			"SpawnMonster::checkSpawnMonster",
 			"SpawnMonster::scheduleSpawn",
+			"SpawnMonster::startup",
 			"SpawnNpc::checkSpawnNpc",
 			"Webhook::run",
 			"Protocol::sendRecvMessageCallback",