diff --git a/ChatRPG/API/HttpMessageHandlerFactory.cs b/ChatRPG/API/HttpMessageHandlerFactory.cs
index 9fa9ce8..4d874d5 100644
--- a/ChatRPG/API/HttpMessageHandlerFactory.cs
+++ b/ChatRPG/API/HttpMessageHandlerFactory.cs
@@ -28,7 +28,7 @@ public HttpMessageHandler CreateHandler(string name)
     private static HttpResponseMessage GenerateMockResponse(HttpRequestMessage request)
     {
         Console.Write("Please enter mocked API response: ");
-        string input = Console.ReadLine();
+        string? input = Console.ReadLine();
         StringContent responseContent = new StringContent($$"""
                                                   {
                                                       "id": "chatcmpl-000",
diff --git a/ChatRPG/API/OpenAiLlmClient.cs b/ChatRPG/API/OpenAiLlmClient.cs
index bb48e4d..1324eef 100644
--- a/ChatRPG/API/OpenAiLlmClient.cs
+++ b/ChatRPG/API/OpenAiLlmClient.cs
@@ -13,7 +13,7 @@ public class OpenAiLlmClient : IOpenAiLlmClient
 
     public OpenAiLlmClient(IConfiguration configuration, IHttpClientFactory httpClientFactory)
     {
-        _openAiApi = new OpenAIAPI(configuration.GetSection("ApiKeys").GetValue<string>("OpenAI") ?? string.Empty);
+        _openAiApi = new OpenAIAPI(configuration.GetSection("ApiKeys")?.GetValue<string>("OpenAI"));
         _openAiApi.Chat.DefaultChatRequestArgs.Model = Model;
         _openAiApi.Chat.DefaultChatRequestArgs.Temperature = Temperature;
         _openAiApi.HttpClientFactory = httpClientFactory;
diff --git a/ChatRPG/Areas/Identity/RevalidatingIdentityAuthenticationStateProvider.cs b/ChatRPG/Areas/Identity/RevalidatingIdentityAuthenticationStateProvider.cs
index b869596..10e59d2 100644
--- a/ChatRPG/Areas/Identity/RevalidatingIdentityAuthenticationStateProvider.cs
+++ b/ChatRPG/Areas/Identity/RevalidatingIdentityAuthenticationStateProvider.cs
@@ -31,7 +31,7 @@ protected override async Task<bool> ValidateAuthenticationStateAsync(
         IServiceScope scope = _scopeFactory.CreateScope();
         try
         {
-            UserManager<TUser?> userManager = scope.ServiceProvider.GetRequiredService<UserManager<TUser>>();
+            UserManager<TUser> userManager = scope.ServiceProvider.GetRequiredService<UserManager<TUser>>();
             return await ValidateSecurityStampAsync(userManager, authenticationState.User);
         }
         finally
@@ -47,7 +47,7 @@ protected override async Task<bool> ValidateAuthenticationStateAsync(
         }
     }
 
-    private async Task<bool> ValidateSecurityStampAsync(UserManager<TUser?> userManager, ClaimsPrincipal principal)
+    private async Task<bool> ValidateSecurityStampAsync(UserManager<TUser> userManager, ClaimsPrincipal principal)
     {
         TUser? user = await userManager.GetUserAsync(principal);
         if (user == null)
diff --git a/ChatRPG/Data/Models/Character.cs b/ChatRPG/Data/Models/Character.cs
index d438b15..c899c66 100644
--- a/ChatRPG/Data/Models/Character.cs
+++ b/ChatRPG/Data/Models/Character.cs
@@ -34,7 +34,7 @@ public Character(Campaign campaign, CharacterType type, string name, string desc
     public string Description { get; private set; } = null!;
     public int MaxHealth { get; private set; }
     public int CurrentHealth { get; private set; }
-    public ICollection<CharacterAbility> CharacterAbilities { get; } = new List<CharacterAbility>();
+    public ICollection<CharacterAbility?> CharacterAbilities { get; } = new List<CharacterAbility?>();
 
     /// <summary>
     /// Adjust the current health of this character.
@@ -54,9 +54,9 @@ public void AdjustHealth(int value)
     /// </summary>
     /// <param name="ability">The ability to add.</param>
     /// <returns>The created <see cref="CharacterAbility"/> entity.</returns>
-    public CharacterAbility AddAbility(Ability ability)
+    public CharacterAbility? AddAbility(Ability ability)
     {
-        CharacterAbility charAbility = CharacterAbilities.FirstOrDefault(a => a!.Ability == ability, null);
+        CharacterAbility? charAbility = CharacterAbilities.FirstOrDefault(a => a!.Ability == ability, null);
         if (charAbility is not null)
         {
             return charAbility;
diff --git a/ChatRPG/Pages/Shared/_Layout.cshtml b/ChatRPG/Pages/Shared/_Layout.cshtml
index 46212bd..1118ede 100644
--- a/ChatRPG/Pages/Shared/_Layout.cshtml
+++ b/ChatRPG/Pages/Shared/_Layout.cshtml
@@ -58,7 +58,7 @@
         <div class="container">
         &copy; 2023 - ChatRPG
             @{
-                string foundPrivacy = Url.Page("/Privacy", new { area = "" });
+                string? foundPrivacy = Url.Page("/Privacy", new { area = "" });
             }
             @if (foundPrivacy != null)
             {
diff --git a/ChatRPG/Program.cs b/ChatRPG/Program.cs
index 3d84b83..d92bc65 100644
--- a/ChatRPG/Program.cs
+++ b/ChatRPG/Program.cs
@@ -51,7 +51,7 @@
         ApplicationDbContext dbContext = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
         dbContext.Database.Migrate();
 
-        UserManager<User?> userManager = scope.ServiceProvider.GetRequiredService<UserManager<User>>();
+        UserManager<User> userManager = scope.ServiceProvider.GetRequiredService<UserManager<User>>();
         const string username = "test";
         User? user = await userManager.FindByNameAsync(username);
         if (user == null)