Add more assertions to prevent segfaults.

src/Battling/Models/Creature.cpp

@@ -122,6 +122,8 @@ const ArbUt::BorrowedPtr<CreatureLib::Battling::BattleSide>& Battling::Creature:
 bool Battling::Creature::IsFainted() const noexcept { return this->_currentHealth == 0; }
 
 void Battling::Creature::OnFaint() {
+    AssertNotNull(_battle)
+    AssertNotNull(_side)
     // HOOK: On Faint
     if (_battle != nullptr) {
         _battle->TriggerEventListener<FaintEvent>(this);
@@ -148,7 +150,7 @@ void Battling::Creature::Damage(uint32_t damage, Battling::DamageSource source)
     }
     _currentHealth = newHealth;
 
-    if (IsFainted() && damage > 0) {
+    if (IsFainted() && damage > 0 && battle != nullptr) {
         OnFaint();
     }
 }