diff --git a/core/src/cubos/core/ecs/types.cpp b/core/src/cubos/core/ecs/types.cpp
index 63e3bf5d5..95851c583 100644
--- a/core/src/cubos/core/ecs/types.cpp
+++ b/core/src/cubos/core/ecs/types.cpp
@@ -39,11 +39,13 @@ void Types::add(const reflection::Type& type, Kind kind)
 
 DataTypeId Types::id(const reflection::Type& type) const
 {
+    CUBOS_ASSERT(mTypes.contains(type), "Type {} not registered", type.name());
     return mTypes.at(type);
 }
 
 DataTypeId Types::id(const std::string& name) const
 {
+    CUBOS_ASSERT(mNames.contains(name), "Type {} not registered", name);
     return mNames.at(name);
 }
 
diff --git a/core/src/cubos/core/ecs/world.cpp b/core/src/cubos/core/ecs/world.cpp
index ede9df5d1..6100ebea5 100644
--- a/core/src/cubos/core/ecs/world.cpp
+++ b/core/src/cubos/core/ecs/world.cpp
@@ -144,7 +144,7 @@ void World::relate(Entity from, Entity to, const reflection::Type& type, void* v
     CUBOS_ASSERT(this->isAlive(to));
 
     auto dataType = mTypes.id(type);
-    CUBOS_ASSERT(mTypes.isRelation(dataType));
+    CUBOS_ASSERT(mTypes.isRelation(dataType), "Type {} is not registered as a relation", type.name());
 
     // Create a sparse relation table identifier from the archetypes of both entities.
     auto fromArchetype = mEntityPool.archetype(from.index);
@@ -230,7 +230,7 @@ auto World::Components::end() -> Iterator
 auto World::Components::add(const reflection::Type& type, void* value) -> Components&
 {
     auto typeId = mWorld.mTypes.id(type);
-    CUBOS_ASSERT(mWorld.mTypes.isComponent(typeId), "Type '{}' is not registered as a component", type.name());
+    CUBOS_ASSERT(mWorld.mTypes.isComponent(typeId), "Type {} is not registered as a component", type.name());
     auto columnId = ColumnId::make(typeId);
 
     auto oldArchetype = mWorld.mEntityPool.archetype(mEntity.index);
@@ -265,7 +265,7 @@ auto World::Components::add(const reflection::Type& type, void* value) -> Compon
 auto World::Components::remove(const reflection::Type& type) -> Components&
 {
     auto typeId = mWorld.mTypes.id(type);
-    CUBOS_ASSERT(mWorld.mTypes.isComponent(typeId), "Type '{}' is not registered as a component", type.name());
+    CUBOS_ASSERT(mWorld.mTypes.isComponent(typeId), "Type {} is not registered as a component", type.name());
     auto columnId = ColumnId::make(typeId);
 
     // If the old archetype doesn't contain this component type, then we don't do anything.
diff --git a/core/tests/ecs/utils.hpp b/core/tests/ecs/utils.hpp
index 8c954a4c2..76a58d5b8 100644
--- a/core/tests/ecs/utils.hpp
+++ b/core/tests/ecs/utils.hpp
@@ -76,4 +76,7 @@ inline void setupWorld(cubos::core::ecs::World& world)
     world.registerComponent<DetectDestructorComponent>();
     world.registerComponent<EntityArrayComponent>();
     world.registerComponent<EntityDictionaryComponent>();
+    world.registerRelation<EmptyRelation>();
+    world.registerRelation<IntegerRelation>();
+    world.registerRelation<DetectDestructorRelation>();
 }
diff --git a/core/tests/ecs/world.cpp b/core/tests/ecs/world.cpp
index eee00043b..60684f48f 100644
--- a/core/tests/ecs/world.cpp
+++ b/core/tests/ecs/world.cpp
@@ -133,4 +133,80 @@ TEST_CASE("ecs::World")
 
         CHECK(destroyed);
     }
+
+    SUBCASE("add and remove relations")
+    {
+        // Create three entities.
+        auto foo = world.create();
+        auto bar = world.create();
+        auto baz = world.create();
+
+        bool fooBarFlag = false;
+        bool barBazFlag = false;
+        bool fooBazFlag = false;
+        bool fooFooFlag = false;
+
+        // Relate foo to bar.
+        REQUIRE_FALSE(world.related<DetectDestructorRelation>(foo, bar));
+        world.relate(foo, bar, DetectDestructorRelation{{&fooBarFlag}});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, bar));
+
+        // Relate bar to baz.
+        REQUIRE_FALSE(world.related<DetectDestructorRelation>(bar, baz));
+        world.relate(bar, baz, DetectDestructorRelation{{&barBazFlag}});
+        REQUIRE(world.related<DetectDestructorRelation>(bar, baz));
+
+        // Relate foo to baz.
+        REQUIRE_FALSE(world.related<DetectDestructorRelation>(foo, baz));
+        world.relate(foo, baz, DetectDestructorRelation{{&fooBazFlag}});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, baz));
+
+        // Relate foo to foo.
+        REQUIRE_FALSE(world.related<DetectDestructorRelation>(foo, foo));
+        world.relate(foo, foo, DetectDestructorRelation{{&fooFooFlag}});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, foo));
+
+        // Nothing should have been destroyed yet.
+        CHECK_FALSE(fooBarFlag);
+        CHECK_FALSE(barBazFlag);
+        CHECK_FALSE(fooBazFlag);
+        CHECK_FALSE(fooFooFlag);
+
+        // Remove the relation between foo and bar and add it again.
+        world.unrelate<DetectDestructorRelation>(foo, bar);
+        CHECK(fooBarFlag);
+        CHECK_FALSE(barBazFlag);
+        CHECK_FALSE(fooBazFlag);
+        CHECK_FALSE(fooFooFlag);
+        fooBarFlag = false;
+        world.relate(foo, bar, DetectDestructorRelation{{&fooBarFlag}});
+
+        // Destroy bar.
+        world.destroy(bar);
+        CHECK(fooBarFlag);
+        CHECK(barBazFlag);
+        CHECK_FALSE(fooBazFlag);
+        CHECK_FALSE(fooFooFlag);
+
+        // Destroy foo.
+        world.destroy(foo);
+        CHECK(fooBazFlag);
+        CHECK(fooFooFlag);
+    }
+
+    SUBCASE("relations are correctly destructed when the world is destroyed")
+    {
+        bool destroyed = false;
+
+        // Create a world with an entity and a relation and immediately destroy it.
+        {
+            World world{};
+            setupWorld(world);
+            auto foo = world.create();
+            world.relate(foo, foo, DetectDestructorRelation{{&destroyed}});
+            CHECK_FALSE(destroyed);
+        }
+
+        CHECK(destroyed);
+    }
 }