diff --git a/inc-c/entity.h b/inc-c/entity.h
index 34b0a64..de7d6d0 100644
--- a/inc-c/entity.h
+++ b/inc-c/entity.h
@@ -2,7 +2,10 @@
 #ifndef MT_ENTITY_H
 #define MT_ENTITY_H
 
+#include <stdbool.h>
 #include <stdint.h>
+#include <stddef.h>
+#include <alphaumlaut/maths.h>
 
 typedef struct MtEntity MtEntity;
 
@@ -21,4 +24,17 @@ struct MtEntity
     uint32_t shadow_id;
 };
 
+MtEntity mt_summon(void *context_ptr);
+void mt_delete(MtEntity entity);
+
+void mt_tag_bool(MtEntity entity, const char *name, bool boolean);
+void mt_tag_int(MtEntity entity, const char *name, int64_t integer);
+void mt_tag_float(MtEntity entity, const char *name, double real);
+void mt_tag_str(MtEntity entity, const char *name, char *string);
+void mt_tag_ptr(MtEntity entity, const char *name, void *pointer);
+void mt_tag_vec2f(MtEntity entity, const char *name, AuVec2f vec2f);
+void mt_tag_vec3f(MtEntity entity, const char *name, AuVec3f vec3f);
+void mt_tag_vec4f(MtEntity entity, const char *name, AuVec4f vec4f);
+void mt_tag_ref(MtEntity entity, const char *name, MtEntity reference);
+
 #endif // MT_ENTITY_H
diff --git a/inc-c/shadow-tag.h b/inc-c/shadow-tag.h
index 5508177..ec25bfc 100644
--- a/inc-c/shadow-tag.h
+++ b/inc-c/shadow-tag.h
@@ -16,15 +16,16 @@ typedef struct MtShadowTagSystem MtShadowTagSystem;
 
 typedef enum
 {
+    MT_SHADOW_TAG_UNUSED = 0,
     MT_SHADOW_TAG_INTEGER,
     MT_SHADOW_TAG_BOOLEAN,
-    MT_SHADOW_TAG_DECIMAL,
+    MT_SHADOW_TAG_REAL,
     MT_SHADOW_TAG_STRING,
     MT_SHADOW_TAG_RAW_POINTER,
     MT_SHADOW_TAG_VECTOR_2,
     MT_SHADOW_TAG_VECTOR_3,
     MT_SHADOW_TAG_VECTOR_4,
-    MT_SHADOW_TAG_SUB_ENTITY,
+    MT_SHADOW_TAG_REFERENCE,
     MT_SHADOW_TAG_RESOURCE
 
 } MtShadowTagType;
@@ -40,13 +41,13 @@ struct MtShadowTag
     {
         bool boolean;
         int64_t integer;
-        double decimal;
+        double real;
         char *string;
         void *raw_pointer;
         AuVec2f vec2f;
         AuVec3f vec3f;
         AuVec4f vec4f;
-        MtEntity entity;
+        MtEntity reference;
     } data;
 };
 
diff --git a/src-c/entity.c b/src-c/entity.c
new file mode 100644
index 0000000..42b7271
--- /dev/null
+++ b/src-c/entity.c
@@ -0,0 +1,98 @@
+#include <entity.h>
+#include <context.h>
+#include <shadow-registry.h>
+
+MtEntity mt_summon(void *context_ptr)
+{
+    MtContext *context = context_ptr;
+    MtShadow *shadow = mt_create_shadow(context->shadow_registry);
+    MtEntity entity;
+    entity.context = context_ptr;
+    entity.shadow_id = shadow->identifier;
+    return entity;
+}
+
+void mt_delete(MtEntity entity)
+{
+    MtContext *context = entity.context;
+    MtShadow *shadow = mt_lookup_shadow(context->shadow_registry, entity.shadow_id);
+    mt_delete_shadow(context->shadow_registry, shadow);
+}
+
+MtShadowTag * mt_get_and_name_tag_for_entity(MtEntity entity, const char *name)
+{
+    MtContext *context = entity.context;
+    MtShadow *shadow = mt_lookup_shadow(context->shadow_registry, entity.shadow_id);
+    if(shadow->tag_chain_start == NULL)
+        shadow->tag_chain_start = (entity.context);
+    else
+        shadow->tag_chain_start = mt_alloc_shadow_tag_before(shadow->tag_chain_start);
+    return shadow->tag_chain_start;
+}
+
+void mt_tag_bool(MtEntity entity, const char *name, bool boolean)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_BOOLEAN;
+    tag->data.boolean = boolean;
+}
+
+void mt_tag_int(MtEntity entity, const char *name, int64_t integer)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_INTEGER;
+    tag->data.integer = integer;
+}
+
+void mt_tag_float(MtEntity entity, const char *name, double real)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_REAL;
+    tag->data.real = real;
+}
+
+void mt_tag_str(MtEntity entity, const char *name, char *string)
+{
+    // TODO: Allocate the string in an arena allocator which is
+    // stored in, and deleted with, the entity shadow.
+
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_STRING;
+    tag->data.string = string;
+}
+
+void mt_tag_ptr(MtEntity entity, const char *name, void *pointer)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_RAW_POINTER;
+    tag->data.raw_pointer = pointer;
+}
+
+void mt_tag_vec2f(MtEntity entity, const char *name, AuVec2f vec2f)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_VECTOR_2;
+    tag->data.vec2f = vec2f;
+}
+
+void mt_tag_vec3f(MtEntity entity, const char *name, AuVec3f vec3f)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_VECTOR_3;
+    tag->data.vec3f = vec3f;
+}
+
+void mt_tag_vec4f(MtEntity entity, const char *name, AuVec4f vec4f)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_VECTOR_4;
+    tag->data.vec4f = vec4f;
+}
+
+void mt_tag_ref(MtEntity entity, const char *name, MtEntity reference)
+{
+    MtShadowTag *tag = mt_get_and_name_tag_for_entity(entity, name);
+    tag->type = MT_SHADOW_TAG_REFERENCE;
+    tag->data.reference = reference;
+}
+