diff --git a/lib/nw/kernel/Rules.cpp b/lib/nw/kernel/Rules.cpp
index a484d1042..29552d704 100644
--- a/lib/nw/kernel/Rules.cpp
+++ b/lib/nw/kernel/Rules.cpp
@@ -12,6 +12,19 @@ const std::type_index Rules::type_index{typeid(Rules)};
 
 Rules::Rules(MemoryResource* scope)
     : Service(scope)
+    , baseitems{allocator()}
+    , classes{allocator()}
+    , feats{allocator()}
+    , races{allocator()}
+    , spells{allocator()}
+    , spellschools{allocator()}
+    , skills{allocator()}
+    , master_feats{allocator()}
+    , modifiers{allocator()}
+    , phenotypes{allocator()}
+    , appearances{allocator()}
+    , placeables{allocator()}
+    , traps{allocator()}
 {
 }
 
@@ -20,22 +33,6 @@ Rules::~Rules()
     clear();
 }
 
-void Rules::clear()
-{
-    modifiers.clear();
-    baseitems.clear();
-    classes.clear();
-    feats.clear();
-    races.clear();
-    spells.clear();
-    skills.clear();
-    master_feats.clear();
-    appearances.clear();
-    phenotypes.clear();
-    traps.clear();
-    placeables.clear();
-}
-
 void Rules::initialize(ServiceInitTime time)
 {
     if (time != ServiceInitTime::kernel_start && time != ServiceInitTime::module_post_load) {
diff --git a/lib/nw/kernel/Rules.hpp b/lib/nw/kernel/Rules.hpp
index 3450bc261..dcd076bb1 100644
--- a/lib/nw/kernel/Rules.hpp
+++ b/lib/nw/kernel/Rules.hpp
@@ -29,9 +29,6 @@ struct Rules : public Service {
     /// Initializes rules system
     virtual void initialize(ServiceInitTime time) override;
 
-    /// Clears rules system of all rules and cached 2da files
-    virtual void clear() override;
-
     /// Gets attack functions
     [[nodiscard]] const AttackFuncs& attack_functions() const noexcept;
 
diff --git a/lib/nw/rules/Class.hpp b/lib/nw/rules/Class.hpp
index 1d92650dd..e465f7127 100644
--- a/lib/nw/rules/Class.hpp
+++ b/lib/nw/rules/Class.hpp
@@ -92,7 +92,14 @@ struct ClassArray {
         InternedString,
         Class,
         InternedStringHash,
-        InternedStringEq>;
+        InternedStringEq,
+        Allocator<std::pair<const InternedString, const ClassInfo>>>;
+
+    ClassArray(MemoryResource* allocator = kernel::global_allocator())
+        : entries(allocator)
+        , constant_to_index(allocator)
+    {
+    }
 
     const ClassInfo* get(Class class_) const noexcept;
     bool is_valid(Class class_) const noexcept;
@@ -120,7 +127,7 @@ struct ClassArray {
     std::set<Vector<int>> attack_tables;
     Vector<int> stat_gain_tables;
 
-    Vector<ClassInfo> entries;
+    PVector<ClassInfo> entries;
     map_type constant_to_index;
 };
 
diff --git a/lib/nw/rules/feats.cpp b/lib/nw/rules/feats.cpp
index 6bcfb391b..326926f36 100644
--- a/lib/nw/rules/feats.cpp
+++ b/lib/nw/rules/feats.cpp
@@ -52,6 +52,11 @@ FeatInfo::FeatInfo(const TwoDARowView& tda)
 // -- Master Feats ------------------------------------------------------------
 // ----------------------------------------------------------------------------
 
+MasterFeatRegistry::MasterFeatRegistry(MemoryResource* allocator)
+    : allocator_(allocator)
+{
+}
+
 const ModifierVariant& MasterFeatRegistry::get_bonus(MasterFeat mfeat) const
 {
     return bonuses_[*mfeat];
diff --git a/lib/nw/rules/feats.hpp b/lib/nw/rules/feats.hpp
index b74488efa..a714fb02d 100644
--- a/lib/nw/rules/feats.hpp
+++ b/lib/nw/rules/feats.hpp
@@ -86,6 +86,8 @@ inline bool operator==(const MasterFeatEntry& lhs, const MasterFeatEntry& rhs)
 }
 
 struct MasterFeatRegistry {
+    MasterFeatRegistry(MemoryResource* allocator = nw::kernel::global_allocator());
+
     template <typename T>
     void add(T type, MasterFeat mfeat, Feat feat);
     void clear() noexcept;
@@ -100,6 +102,7 @@ struct MasterFeatRegistry {
 private:
     Vector<MasterFeatEntry> entries_;
     Vector<ModifierVariant> bonuses_;
+    MemoryResource* allocator_ = nullptr;
 };
 
 template <typename T>
diff --git a/lib/nw/rules/rule_type.hpp b/lib/nw/rules/rule_type.hpp
index a10338818..6ed5f3a2e 100644
--- a/lib/nw/rules/rule_type.hpp
+++ b/lib/nw/rules/rule_type.hpp
@@ -2,6 +2,7 @@
 
 #include "../util/InternedString.hpp"
 
+#include "../kernel/Kernel.hpp"
 #include <absl/container/flat_hash_map.h>
 #include <nlohmann/json_fwd.hpp>
 
@@ -155,7 +156,14 @@ struct RuleTypeArray {
         InternedString,
         RuleType,
         InternedStringHash,
-        InternedStringEq>;
+        InternedStringEq,
+        Allocator<std::pair<const InternedString, const RuleType>>>;
+
+    RuleTypeArray(MemoryResource* allocator = kernel::global_allocator())
+        : entries(allocator)
+        , constant_to_index(allocator)
+    {
+    }
 
     const RuleTypeInfo* get(RuleType type) const noexcept
     {
@@ -187,7 +195,7 @@ struct RuleTypeArray {
         }
     }
 
-    Vector<RuleTypeInfo> entries;
+    PVector<RuleTypeInfo> entries;
     map_type constant_to_index;
 };
 
diff --git a/lib/nw/rules/system.cpp b/lib/nw/rules/system.cpp
index 25fd40585..9cdbcdeba 100644
--- a/lib/nw/rules/system.cpp
+++ b/lib/nw/rules/system.cpp
@@ -142,6 +142,11 @@ nw::Modifier make_modifier(nw::ModifierType type, nw::ModifierVariant value,
     };
 }
 
+ModifierRegistry::ModifierRegistry(MemoryResource* allocator)
+    : allocator_(allocator)
+{
+}
+
 void ModifierRegistry::add(Modifier mod)
 {
     auto it = std::lower_bound(std::begin(entries_), std::end(entries_), mod);
diff --git a/lib/nw/rules/system.hpp b/lib/nw/rules/system.hpp
index b92320d25..2bb647a23 100644
--- a/lib/nw/rules/system.hpp
+++ b/lib/nw/rules/system.hpp
@@ -9,13 +9,9 @@
 #include "rule_type.hpp"
 #include "system.hpp"
 
+#include <absl/container/fixed_array.h>
 #include <absl/container/inlined_vector.h>
 
-#include <limits>
-#include <optional>
-#include <string>
-#include <variant>
-
 namespace nw {
 
 struct Class;
@@ -91,7 +87,7 @@ enum struct ModifierSource {
 };
 
 struct ModifierResult {
-    ModifierResult() { };
+    ModifierResult() {};
     ModifierResult(int value);
     ModifierResult(float value);
     ModifierResult(DamageRoll value);
@@ -187,6 +183,8 @@ struct ModifierRegistry {
     using iterator = Storage::iterator;
     using const_iterator = Storage::const_iterator;
 
+    ModifierRegistry(MemoryResource* allocator = nw::kernel::global_allocator());
+
     /// Adds a modifier to the system
     void add(Modifier mod);
 
@@ -232,6 +230,7 @@ struct ModifierRegistry {
 
 private:
     Storage entries_;
+    MemoryResource* allocator_ = nullptr;
 };
 
 } // namespace nw