diff --git a/src/module/actor/actor-data.ts b/src/module/actor/actor-data.ts
index d6575c24..1ddcb9c9 100644
--- a/src/module/actor/actor-data.ts
+++ b/src/module/actor/actor-data.ts
@@ -1,2 +1,26 @@
+export type DS4ActorDataType = EntityData<DS4ActorData>;
+
 // TODO: Actually add a type for data
-export type DS4ActorDataType = unknown;
+export class DS4ActorData {
+    public attributes: DS4ActorDataAttributes;
+    public traits: DS4ActorDataTraits;
+}
+
+class DS4ActorDataAttributes {
+    public body: ExpandableAttribute<number>;
+    public mobility: ExpandableAttribute<number>;
+    public mind: ExpandableAttribute<number>;
+}
+
+class ExpandableAttribute<T extends any> {
+    public initial: T;
+}
+
+class DS4ActorDataTraits {
+    public strength: ExpandableAttribute<number>;
+    public constitution: ExpandableAttribute<number>;
+    public agility: ExpandableAttribute<number>;
+    public dexterity: ExpandableAttribute<number>;
+    public intellect: ExpandableAttribute<number>;
+    public aura: ExpandableAttribute<number>;
+}
diff --git a/src/module/actor/actor-sheet.ts b/src/module/actor/actor-sheet.ts
index 4a16bfa7..57128b34 100644
--- a/src/module/actor/actor-sheet.ts
+++ b/src/module/actor/actor-sheet.ts
@@ -21,9 +21,9 @@ export class DS4ActorSheet extends ActorSheet<DS4ActorDataType, DS4Actor> {
 
     /** @override */
     getData(): ActorSheetData<DS4ActorDataType> {
-        // TODO: replace ["..."] access with .
         const data = super.getData();
-        data["dtypes"] = ["String", "Number", "Boolean"];
+        const checkboxTypes = [typeof String, typeof Number, typeof Boolean];
+        console.log(data.data["attributes"]);
         for (const attr of Object.values(data.data["attributes"])) {
             attr["isCheckbox"] = attr["dtype"] === "Boolean";
         }
@@ -99,7 +99,7 @@ export class DS4ActorSheet extends ActorSheet<DS4ActorDataType, DS4Actor> {
         const dataset = element.dataset;
 
         if (dataset.roll) {
-            const roll = new Roll(dataset.roll, this.actor.data.data as Record<string, unknown>);
+            const roll = new Roll(dataset.roll, this.actor.data.data);
             const label = dataset.label ? `Rolling ${dataset.label}` : "";
             roll.roll().toMessage({
                 speaker: ChatMessage.getSpeaker({ actor: this.actor }),
diff --git a/src/module/actor/actor.ts b/src/module/actor/actor.ts
index 38292ed7..e1f806b0 100644
--- a/src/module/actor/actor.ts
+++ b/src/module/actor/actor.ts
@@ -1,4 +1,4 @@
-import { DS4ActorDataType } from "./actor-data";
+import { DS4ActorData, DS4ActorDataType } from "./actor-data";
 
 /**
  * Extend the base Actor entity by defining a custom roll data structure which is ideal for the Simple system.
@@ -13,21 +13,20 @@ export class DS4Actor extends Actor<DS4ActorDataType> {
 
     _prepareCombatValues(data: ActorData<DS4ActorDataType>): void {
         const hitPointsModifier = getProperty(data, "data.combatValues.hitPoints.modifier") || 0;
+        // data.data seems to get initialized with the enitity's data
+        const actorData = (data.data as unknown) as DS4ActorData;
         setProperty(
             data,
             "data.combatValues.hitPoints.max",
-            data.data["attributes"]["body"].initial + // TODO: replace ["..."]
-                data.data["traits"]["constitution"].initial + // TODO: replace ["..."]
-                10 +
-                hitPointsModifier,
+            actorData.attributes.body.initial + actorData.traits.constitution.initial + 10 + hitPointsModifier,
         );
 
         const defenseModifier = getProperty(data, "data.combatValues.defense.modifier") || 0;
         setProperty(
             data,
             "data.combatValues.defense.value",
-            data.data["attributes"]["body"].initial + // TODO: replace ["..."]
-                data.data["traits"]["constitution"].initial + // TODO: replace ["..."]
+            actorData.attributes.body.initial +
+                actorData.traits.constitution.initial +
                 this._getArmorValue() +
                 defenseModifier,
         );
diff --git a/src/module/item/item-sheet.ts b/src/module/item/item-sheet.ts
index d9258449..eff93c0d 100644
--- a/src/module/item/item-sheet.ts
+++ b/src/module/item/item-sheet.ts
@@ -6,7 +6,7 @@ import { DS4ItemDataType } from "./item-data";
  * Extend the basic ItemSheet with some very simple modifications
  * @extends {ItemSheet}
  */
-export class DS4ItemSheet extends ItemSheet<DS4ActorDataType, DS4Item> {
+export class DS4ItemSheet extends ItemSheet<DS4ItemDataType, DS4Item> {
     /** @override */
     static get defaultOptions(): FormApplicationOptions {
         return mergeObject(super.defaultOptions, {