diff --git a/codeforlife/models/__init__.py b/codeforlife/models/__init__.py
index 6cdb83e..4618e0c 100644
--- a/codeforlife/models/__init__.py
+++ b/codeforlife/models/__init__.py
@@ -48,7 +48,7 @@ def update(self, **kwargs):
                 last_saved_at: When these models were last modified.
 
             Returns:
-                The number of models updated.
+                The number of models matched.
             """
 
             kwargs["last_saved_at"] = timezone.now()
diff --git a/codeforlife/user/migrations/0001_initial.py b/codeforlife/user/migrations/0001_initial.py
index bce9732..33e9816 100644
--- a/codeforlife/user/migrations/0001_initial.py
+++ b/codeforlife/user/migrations/0001_initial.py
@@ -1,4 +1,4 @@
-# Generated by Django 3.2.20 on 2023-12-11 17:42
+# Generated by Django 3.2.20 on 2023-12-15 11:16
 
 from django.conf import settings
 import django.core.validators
@@ -25,7 +25,7 @@ class Migration(migrations.Migration):
                 ('is_superuser', models.BooleanField(default=False, help_text='Designates that this user has all permissions without explicitly assigning them.', verbose_name='superuser status')),
                 ('last_saved_at', models.DateTimeField(auto_now=True, help_text='Record the last time the model was saved. This is used by our data warehouse to know what data was modified since the last scheduled data transfer from the database to the data warehouse.', verbose_name='last saved at')),
                 ('delete_after', models.DateTimeField(blank=True, help_text="When this data is scheduled for deletion. Set to null if not scheduled for deletion. This is used by our data warehouse to transfer data that's been scheduled for deletion before it's actually deleted. Data will actually be deleted in a CRON job after this point in time.", null=True, verbose_name='delete after')),
-                ('first_name', models.CharField(blank=True, max_length=150, verbose_name='first name')),
+                ('first_name', models.CharField(max_length=150, verbose_name='first name')),
                 ('last_name', models.CharField(blank=True, max_length=150, null=True, verbose_name='last name')),
                 ('email', models.EmailField(blank=True, max_length=254, null=True, unique=True, verbose_name='email address')),
                 ('is_staff', models.BooleanField(default=False, help_text='Designates whether the user can log into this admin site.', verbose_name='staff status')),
@@ -114,7 +114,7 @@ class Migration(migrations.Migration):
                 ('last_saved_at', models.DateTimeField(auto_now=True, help_text='Record the last time the model was saved. This is used by our data warehouse to know what data was modified since the last scheduled data transfer from the database to the data warehouse.', verbose_name='last saved at')),
                 ('delete_after', models.DateTimeField(blank=True, help_text="When this data is scheduled for deletion. Set to null if not scheduled for deletion. This is used by our data warehouse to transfer data that's been scheduled for deletion before it's actually deleted. Data will actually be deleted in a CRON job after this point in time.", null=True, verbose_name='delete after')),
                 ('is_admin', models.BooleanField(default=False, help_text='Designates if the teacher has admin privileges.', verbose_name='is administrator')),
-                ('school', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='teachers', to='user.school')),
+                ('school', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='teachers', to='user.school')),
             ],
             options={
                 'verbose_name': 'teacher',
diff --git a/codeforlife/user/models/otp_bypass_token.py b/codeforlife/user/models/otp_bypass_token.py
index 164f59b..6fd303c 100644
--- a/codeforlife/user/models/otp_bypass_token.py
+++ b/codeforlife/user/models/otp_bypass_token.py
@@ -65,10 +65,7 @@ def key(otp_bypass_token: OtpBypassToken):
             for user_id, group in groupby(otp_bypass_tokens, key=key):
                 if (
                     len(list(group))
-                    + OtpBypassToken.objects.filter(
-                        user_id=user_id,
-                        delete_after__isnull=True,
-                    ).count()
+                    + OtpBypassToken.objects.filter(user_id=user_id).count()
                     > OtpBypassToken.max_count
                 ):
                     raise OtpBypassToken.max_count_validation_error
@@ -99,10 +96,7 @@ class Meta(TypedModelMeta):
     def save(self, *args, **kwargs):
         if self.id is None:
             if (
-                OtpBypassToken.objects.filter(
-                    user=self.user,
-                    delete_after__isnull=True,
-                ).count()
+                OtpBypassToken.objects.filter(user=self.user).count()
                 >= OtpBypassToken.max_count
             ):
                 raise OtpBypassToken.max_count_validation_error
@@ -116,10 +110,10 @@ def check_token(self, token: str):
             token: Token to check.
 
         Returns:
-            A boolean designating if the token is matches.
+            A boolean designating if the token matches.
         """
 
-        if not self.delete_after and check_password(token, self.token):
+        if check_password(token, self.token):
             self.delete()
             return True
         return False
diff --git a/codeforlife/user/models/student.py b/codeforlife/user/models/student.py
index 2ab241c..63b938d 100644
--- a/codeforlife/user/models/student.py
+++ b/codeforlife/user/models/student.py
@@ -69,10 +69,10 @@ def create_user(self, student: t.Dict[str, t.Any], **fields):
             """Create a user with a student profile.
 
             Args:
-                user: The user fields.
+                student: The student fields.
 
             Returns:
-                A student profile.
+                A user with a student profile.
             """
 
             return _user.User.objects.create_user(
@@ -94,7 +94,7 @@ def bulk_create_users(
                     profile belongs to.
 
             Returns:
-                A list of users that have been assigned their student profile.
+                A list of users with a student profile.
             """
 
             students = [student for (student, _) in student_users]
@@ -141,7 +141,7 @@ class Meta(TypedModelMeta):
 
     @property
     def teacher(self):
-        """The student's teacher (if they have one).
+        """The student's teacher.
 
         Returns:
             The student's class-teacher.
diff --git a/codeforlife/user/models/teacher.py b/codeforlife/user/models/teacher.py
index 51b0bc1..2d1d78a 100644
--- a/codeforlife/user/models/teacher.py
+++ b/codeforlife/user/models/teacher.py
@@ -50,6 +50,7 @@ def create_user(self, teacher: t.Dict[str, t.Any], **fields):
         "user.School",
         related_name="teachers",
         null=True,
+        blank=True,
         on_delete=models.SET_NULL,
     )
 
@@ -72,6 +73,4 @@ def students(self) -> QuerySet["_student.Student"]:
             A queryset
         """
 
-        return _student.Student.objects.filter(
-            klass_id__in=list(self.classes.values_list("id", flat=True)),
-        )
+        return _student.Student.objects.filter(klass__in=self.classes.all())
diff --git a/codeforlife/user/models/user.py b/codeforlife/user/models/user.py
index c4fb54a..72ce213 100644
--- a/codeforlife/user/models/user.py
+++ b/codeforlife/user/models/user.py
@@ -32,7 +32,7 @@
 class User(AbstractBaseUser, WarehouseModel, PermissionsMixin):
     """A user within the CFL system."""
 
-    USERNAME_FIELD = "email"
+    USERNAME_FIELD = "id"
 
     class Manager(BaseUserManager["User"], WarehouseModel.Manager["User"]):
         """
@@ -116,7 +116,6 @@ def create_superuser(self, password: str, first_name: str, **fields):
     first_name = models.CharField(
         _("first name"),
         max_length=150,
-        blank=True,
     )
 
     last_name = models.CharField(