diff --git a/CInterface/Library/SpeciesLibrary.cpp b/CInterface/Library/SpeciesLibrary.cpp
index 763201c..cf5cdaf 100644
--- a/CInterface/Library/SpeciesLibrary.cpp
+++ b/CInterface/Library/SpeciesLibrary.cpp
@@ -2,10 +2,16 @@
 #include "../Core.hpp"
 using namespace PkmnLib::Library;
 
-export const PokemonSpecies* PkmnLib_SpeciesLibrary_FindPreEvolution(const SpeciesLibrary* p,
+export const SpeciesLibrary* PkmnLib_SpeciesLibrary_Construct(size_t initialCapacity) {
+    return new SpeciesLibrary(initialCapacity);
+};
+
+export u8 PkmnLib_SpeciesLibrary_FindPreEvolution(const PokemonSpecies*& out, const SpeciesLibrary* p,
                                                                      const PokemonSpecies* species) {
-    auto v = p->FindPreEvolution(species);
-    if (!v.has_value())
-        return nullptr;
-    return v.value().GetRaw();
+    Try(
+        auto v = p->FindPreEvolution(species);
+        if (!v.has_value())
+            out = nullptr;
+        out = v.value().GetRaw();
+    )
 }
\ No newline at end of file
diff --git a/src/Library/Species/SpeciesLibrary.cpp b/src/Library/Species/SpeciesLibrary.cpp
index 3dbbf94..6c20560 100644
--- a/src/Library/Species/SpeciesLibrary.cpp
+++ b/src/Library/Species/SpeciesLibrary.cpp
@@ -2,15 +2,19 @@
 namespace PkmnLib::Library {
     std::optional<ArbUt::BorrowedPtr<const PokemonSpecies>>
     SpeciesLibrary::FindPreEvolution(const ArbUt::BorrowedPtr<const PokemonSpecies>& species) const noexcept {
-        if (_preEvolutionCache.Has(species)) {
-            return _preEvolutionCache[species];
+        auto tryGet = _preEvolutionCache.TryGet(species);
+        if (tryGet.has_value()) {
+            return tryGet->get();
         }
         for (const auto& s : _values) {
-            auto* pkmn = (PokemonSpecies*)s.second.get();
+            const auto* pkmn = dynamic_cast<const PokemonSpecies*>(s.second.get());
+            if (pkmn == nullptr){
+                continue;
+            }
             for (const auto& evo : pkmn->GetEvolutions()) {
                 if (evo->GetNewSpecies() == species) {
                     auto* non_const = const_cast<SpeciesLibrary*>(this);
-                    non_const->_preEvolutionCache[species] = pkmn;
+                    non_const->_preEvolutionCache.Insert(species, pkmn);
                     return pkmn;
                 }
             }
diff --git a/src/Library/Species/SpeciesLibrary.hpp b/src/Library/Species/SpeciesLibrary.hpp
index a696109..a82825c 100644
--- a/src/Library/Species/SpeciesLibrary.hpp
+++ b/src/Library/Species/SpeciesLibrary.hpp
@@ -10,6 +10,8 @@ namespace PkmnLib::Library {
             _preEvolutionCache;
 
     public:
+        SpeciesLibrary(size_t initialCapacity = 32) : CreatureLib::Library::SpeciesLibrary(initialCapacity) {}
+
         inline std::optional<ArbUt::BorrowedPtr<const PokemonSpecies>>
         TryGet(const ArbUt::BasicStringView& name) const {
             auto res = CreatureLib::Library::SpeciesLibrary::TryGet(name);