Hit dice is specifically blank, all other creatures are ok.

api_v2/migrations/0012_alter_creature_subcategory.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.1.2 on 2024-10-24 14:17
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('api_v2', '0011_merge_20241022_1426'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='creature',
+            name='subcategory',
+            field=models.CharField(blank=True, help_text='What subcategory this creature belongs to.', max_length=100, null=True),
+        ),
+    ]

api_v2/models/creature.py

@@ -42,6 +42,7 @@ class Creature(Object, HasAbilities, HasSenses, HasLanguage, HasSpeed, FromDocum
 
     subcategory = models.CharField(
         max_length=100,
+        blank=True,
         null=True,
         help_text='What subcategory this creature belongs to.'
     )