diff --git a/src/Battling/Pokemon/Pokemon.cpp b/src/Battling/Pokemon/Pokemon.cpp
index 71f641f..16e01fd 100644
--- a/src/Battling/Pokemon/Pokemon.cpp
+++ b/src/Battling/Pokemon/Pokemon.cpp
@@ -1 +1,38 @@
 #include "Pokemon.hpp"
+#include <CreatureLib/Battling/Models/Battle.hpp>
+
+void PkmnLib::Battling::Pokemon::Evolve(ArbUt::BorrowedPtr<const Library::PokemonSpecies> mon,
+                                        ArbUt::BorrowedPtr<const Library::PokemonForme> forme) {
+    _species = mon.ForceAs<const CreatureLib::Library::CreatureSpecies>();
+    _variant = forme.ForceAs<const CreatureLib::Library::SpeciesVariant>();
+
+    ArbUt::Random* rand;
+    if (!_battle.IsNull()) {
+        rand = &_battle->GetRandom()->GetRNG();
+    } else {
+        rand = new ArbUt::Random();
+    }
+
+    if (_gender != CreatureLib::Library::Gender::Genderless && _species->GetGenderRate() != -1) {
+        _gender = _species->GetRandomGender(*rand);
+    } else if (_species->GetGenderRate() == -1 && _gender != CreatureLib::Library::Gender::Genderless) {
+        _gender = CreatureLib::Library::Gender::Genderless;
+    }
+
+    _types.clear();
+    for (auto t : forme->GetTypes()) {
+        _types.insert(t);
+    }
+
+    _activeTalent =
+        std::unique_ptr<CreatureLib::Battling::Script>(_library->LoadScript(ScriptCategory::Talent, GetActiveTalent()));
+
+    auto currentMaxHealth = GetBoostedStat(PkmnLib::Library::Statistic::HealthPoints);
+    RecalculateFlatStats();
+    auto diffHealth = GetBoostedStat(PkmnLib::Library::Statistic::HealthPoints) - currentMaxHealth;
+    _currentHealth += diffHealth;
+    if (_currentHealth < 0)
+        _currentHealth = 0;
+
+    // TODO: Learn moves?
+}
diff --git a/src/Battling/Pokemon/Pokemon.hpp b/src/Battling/Pokemon/Pokemon.hpp
index a6d60c3..18d8933 100644
--- a/src/Battling/Pokemon/Pokemon.hpp
+++ b/src/Battling/Pokemon/Pokemon.hpp
@@ -56,6 +56,9 @@ namespace PkmnLib::Battling {
         inline ArbUt::BorrowedPtr<const PkmnLib::Library::PokemonSpecies> GetPokemonSpecies() const noexcept {
             return _species.As<const PkmnLib::Library::PokemonSpecies>();
         }
+
+        void Evolve(ArbUt::BorrowedPtr<const Library::PokemonSpecies> mon,
+                    ArbUt::BorrowedPtr<const Library::PokemonForme> forme);
     };
 }