diff --git a/src/documents/actor/actor.js b/src/documents/actor/actor.js
index ae4c1112..3277c491 100644
--- a/src/documents/actor/actor.js
+++ b/src/documents/actor/actor.js
@@ -5,7 +5,8 @@
 
 import { DS4 } from "../../config";
 import { createCheckRoll } from "../../dice/check-factory";
-import { mathEvaluator } from "../../expression-evaluation/evaluator";
+import { Evaluator } from "../../expression-evaluation/evaluator";
+import { Validator } from "../../expression-evaluation/validator";
 import { logger } from "../../utils/logger";
 import { getGame } from "../../utils/utils";
 import { DS4ActiveEffect } from "../active-effect";
@@ -59,7 +60,7 @@ export class DS4Actor extends Actor {
   }
 
   /**
-   * The effects that should be applioed to this actor.
+   * The effects that should be applied to this actor.
    * @type {import("../active-effect").DS4ActiveEffect[]}
    * @protected
    */
@@ -90,7 +91,7 @@ export class DS4Actor extends Actor {
       if (condition !== undefined && condition !== "") {
         try {
           const replacedCondition = DS4Actor.replaceFormulaData(condition, { item, actor: this, effect });
-          return replacedCondition !== undefined ? Boolean(mathEvaluator.evaluate(replacedCondition)) : false;
+          return replacedCondition !== undefined ? Boolean(DS4Actor.evaluator.evaluate(replacedCondition)) : false;
         } catch (error) {
           logger.warn(error);
           return false;
@@ -520,6 +521,12 @@ export class DS4Actor extends Actor {
       rejectClose: false,
     });
   }
+
+  static evaluator = new Evaluator({
+    context: Math,
+    predicate: (identifier) =>
+      Validator.defaultPredicate(identifier) || ["includes", "toLowerCase", "toUpperCase"].includes(identifier),
+  });
 }
 
 /**
diff --git a/src/expression-evaluation/evaluator.ts b/src/expression-evaluation/evaluator.ts
index ffc971ac..2cc9409a 100644
--- a/src/expression-evaluation/evaluator.ts
+++ b/src/expression-evaluation/evaluator.ts
@@ -19,7 +19,7 @@ export class Evaluator<Context extends object> {
         get: (t, k) => (k === Symbol.unscopables ? undefined : t[k as keyof typeof t]),
       });
       actualPredicate = (identifier: string) =>
-        predicate(identifier) || Object.getOwnPropertyNames(Math).includes(identifier);
+        predicate(identifier) || Object.getOwnPropertyNames(context).includes(identifier);
     }
     this.validator = new Validator(actualPredicate);
   }