diff --git a/langs/en-ca.json b/langs/en-ca.json
index af66f19..89d1be0 100644
--- a/langs/en-ca.json
+++ b/langs/en-ca.json
@@ -64,6 +64,12 @@
 			"protection": "Protection",
 			"quantity": "Quantity",
 			"rank": "Rank",
+			"rankNames": {
+				"novice": "Novice",
+				"adept": "Adept",
+				"expert": "Expert",
+				"master": "Master"
+			},
 			"range": "Range",
 			"run": "Run",
 			"shield": "Shield",
diff --git a/module/data/Item/Skill.mjs b/module/data/Item/Skill.mjs
index b2429be..d2ace39 100644
--- a/module/data/Item/Skill.mjs
+++ b/module/data/Item/Skill.mjs
@@ -1,7 +1,23 @@
+import { gameTerms } from "../../gameTerms.mjs";
+
+const { fields } = foundry.data;
+
 export class SkillData extends foundry.abstract.TypeDataModel {
 	// MARK: Schema
 	static defineSchema() {
-		return {};
+		const schema = {};
+
+		const advances = {};
+		for (const rank of Object.values(gameTerms.Rank)) {
+			advances[rank] = new fields.StringField({
+				blank: false,
+				nullable: true,
+				initial: null,
+			});
+		};
+		schema.advances = new fields.SchemaField(advances);
+
+		return schema;
 	};
 
 	// MARK: Base Data
diff --git a/module/gameTerms.mjs b/module/gameTerms.mjs
index b893c3b..3406baf 100644
--- a/module/gameTerms.mjs
+++ b/module/gameTerms.mjs
@@ -11,12 +11,12 @@ export const gameTerms = Object.preventExtensions({
 		`Rare`,
 		`Scarce`,
 	],
-	Rank: {
-		NOVICE: `Novice`,
-		ADEPT: `Adept`,
-		EXPERT: `Expert`,
-		MASTER: `Master`,
-	},
+	Rank: Object.freeze({
+		NOVICE: `novice`,
+		ADEPT: `adept`,
+		EXPERT: `expert`,
+		MASTER: `master`,
+	}),
 	Anatomy: Object.freeze({
 		HEAD: `head`,
 		BODY: `body`,