diff --git a/client/Client.cpp b/client/Client.cpp
index 15f7c47a0..174acdb39 100644
--- a/client/Client.cpp
+++ b/client/Client.cpp
@@ -556,6 +556,13 @@ void CClient::invalidatePaths()
 	pathCache.clear();
 }
 
+vstd::RNG & CClient::getRandomGenerator()
+{
+	// Client should use CRandomGenerator::getDefault() for UI logic
+	// Gamestate should never call this method on client!
+	throw std::runtime_error("Illegal access to random number generator from client code!");
+}
+
 std::shared_ptr<const CPathsInfo> CClient::getPathsInfo(const CGHeroInstance * h)
 {
 	assert(h);
diff --git a/client/Client.h b/client/Client.h
index a775ad732..68e116603 100644
--- a/client/Client.h
+++ b/client/Client.h
@@ -218,6 +218,8 @@ public:
 	void showInfoDialog(InfoWindow * iw) override {};
 	void removeGUI() const;
 
+	vstd::RNG & getRandomGenerator() override;
+
 #if SCRIPTING_ENABLED
 	scripting::Pool * getGlobalContextPool() const override;
 #endif
diff --git a/lib/IGameCallback.h b/lib/IGameCallback.h
index a42530adc..493091422 100644
--- a/lib/IGameCallback.h
+++ b/lib/IGameCallback.h
@@ -135,6 +135,9 @@ public:
 	virtual void changeFogOfWar(std::unordered_set<int3> &tiles, PlayerColor player, ETileVisibility mode) = 0;
 	
 	virtual void castSpell(const spells::Caster * caster, SpellID spellID, const int3 &pos) = 0;
+
+	virtual vstd::RNG & getRandomGenerator() = 0;
+
 };
 
 class DLL_LINKAGE CNonConstInfoCallback : public CPrivilegedInfoCallback
diff --git a/lib/gameState/CGameState.cpp b/lib/gameState/CGameState.cpp
index 225eb4566..1be6e9241 100644
--- a/lib/gameState/CGameState.cpp
+++ b/lib/gameState/CGameState.cpp
@@ -185,8 +185,6 @@ void CGameState::init(const IMapService * mapService, StartInfo * si, Load::Prog
 {
 	assert(services);
 	assert(callback);
-	logGlobal->info("\tUsing random seed: %d", si->seedToBeUsed);
-	rand = std::make_unique<CRandomGenerator>(si->seedToBeUsed);
 	scenarioOps = CMemorySerializer::deepCopy(*si).release();
 	initialOpts = CMemorySerializer::deepCopy(*si).release();
 	si = nullptr;
@@ -1966,7 +1964,7 @@ TeamState::TeamState()
 
 vstd::RNG & CGameState::getRandomGenerator()
 {
-	return *rand;
+	return callback->getRandomGenerator();
 }
 
 ArtifactID CGameState::pickRandomArtifact(vstd::RNG & rand, int flags, std::function<bool(ArtifactID)> accepts)
diff --git a/lib/gameState/CGameState.h b/lib/gameState/CGameState.h
index d31f41f16..f5818d59b 100644
--- a/lib/gameState/CGameState.h
+++ b/lib/gameState/CGameState.h
@@ -9,10 +9,10 @@
  */
 #pragma once
 
-#include "bonuses/CBonusSystemNode.h"
-#include "IGameCallback.h"
-#include "LoadProgress.h"
-#include "ConstTransitivePtr.h"
+#include "../bonuses/CBonusSystemNode.h"
+#include "../IGameCallback.h"
+#include "../LoadProgress.h"
+#include "../ConstTransitivePtr.h"
 
 namespace boost
 {
@@ -186,7 +186,11 @@ public:
 		h & teams;
 		h & heroesPool;
 		h & globalEffects;
-		h & rand;
+		if (h.version < Handler::Version::REMOVE_LIB_RNG)
+		{
+			std::string oldStateOfRNG;
+			h & oldStateOfRNG;
+		}
 		h & rumor;
 		h & campaign;
 		h & allocatedArtifacts;
@@ -234,7 +238,6 @@ private:
 
 	// ---- data -----
 	std::shared_ptr<CApplier<CBaseForGSApply>> applier;
-	std::unique_ptr<CRandomGenerator> rand;
 	Services * services;
 
 	/// Pointer to campaign state manager. Nullptr for single scenarios
diff --git a/lib/serializer/ESerializationVersion.h b/lib/serializer/ESerializationVersion.h
index d7d830afc..68e3e1f5a 100644
--- a/lib/serializer/ESerializationVersion.h
+++ b/lib/serializer/ESerializationVersion.h
@@ -56,6 +56,7 @@ enum class ESerializationVersion : int32_t
 	REMOVE_FOG_OF_WAR_POINTER, // 846 - fog of war is serialized as reference instead of pointer
 	SIMPLE_TEXT_CONTAINER_SERIALIZATION, // 847 - text container is serialized using common routine instead of custom approach
 	MAP_FORMAT_ADDITIONAL_INFOS, // 848 - serialize new infos in map format
+	REMOVE_LIB_RNG, // 849 - removed random number generators from library classes
 
-	CURRENT = MAP_FORMAT_ADDITIONAL_INFOS
+	CURRENT = REMOVE_LIB_RNG
 };
diff --git a/server/CGameHandler.cpp b/server/CGameHandler.cpp
index ecd945e2b..a7f303981 100644
--- a/server/CGameHandler.cpp
+++ b/server/CGameHandler.cpp
@@ -549,9 +549,11 @@ void CGameHandler::reinitScripting()
 void CGameHandler::init(StartInfo *si, Load::ProgressAccumulator & progressTracking)
 {
 	if (si->seedToBeUsed == 0)
-	{
 		si->seedToBeUsed = CRandomGenerator::getDefault().nextInt();
-	}
+
+	logGlobal->info("Using random seed: %d", si->seedToBeUsed);
+	randomNumberGenerator = std::make_unique<CRandomGenerator>(si->seedToBeUsed);
+
 	CMapService mapService;
 	gs = new CGameState();
 	gs->preInit(VLC, this);
diff --git a/server/CGameHandler.h b/server/CGameHandler.h
index 4cd5fc573..d6db0a878 100644
--- a/server/CGameHandler.h
+++ b/server/CGameHandler.h
@@ -277,7 +277,7 @@ public:
 	void checkVictoryLossConditions(const std::set<PlayerColor> & playerColors);
 	void checkVictoryLossConditionsForAll();
 
-	vstd::RNG & getRandomGenerator();
+	vstd::RNG & getRandomGenerator() override;
 
 #if SCRIPTING_ENABLED
 	scripting::Pool * getGlobalContextPool() const override;
diff --git a/test/mock/mock_IGameCallback.cpp b/test/mock/mock_IGameCallback.cpp
index 13a6ea0ff..43428b698 100644
--- a/test/mock/mock_IGameCallback.cpp
+++ b/test/mock/mock_IGameCallback.cpp
@@ -31,3 +31,8 @@ void GameCallbackMock::sendAndApply(CPackForClient * pack)
 {
 	upperCallback->apply(pack);
 }
+
+vstd::RNG & GameCallbackMock::getRandomGenerator()
+{
+	throw std::runtime_error("Not implemented!");
+}
diff --git a/test/mock/mock_IGameCallback.h b/test/mock/mock_IGameCallback.h
index 9ab8675f1..78e11699c 100644
--- a/test/mock/mock_IGameCallback.h
+++ b/test/mock/mock_IGameCallback.h
@@ -93,6 +93,8 @@ public:
 	///useful callback methods
 	void sendAndApply(CPackForClient * pack) override;
 
+	vstd::RNG & getRandomGenerator() override;
+
 #if SCRIPTING_ENABLED
 	MOCK_CONST_METHOD0(getGlobalContextPool, scripting::Pool *());
 #endif