diff --git a/common/combat/vulnerable.trait.js b/common/combat/vulnerable.trait.js
index 56af30c..cffb1e3 100644
--- a/common/combat/vulnerable.trait.js
+++ b/common/combat/vulnerable.trait.js
@@ -31,6 +31,7 @@ export class Vulnerable extends Trait {
           playDamagingSound,
         ],
       },
+      vulnerabilities: undefined,
     }
   }
 
@@ -178,16 +179,23 @@ export class Vulnerable extends Trait {
         const damageSpecs = entity.damageSpecs;
         for (let i = 0; i < damageSpecs.length; ++i) {
           const damageSpec = damageSpecs[i];
+          let power = damageSpec.power;
+          // Check if vulnerable to this affinity.
+          if (this.params.vulnerabilities) {
+            if (damageSpec.affinity in this.params.vulnerabilities) {
+              power *= this.params.vulnerabilities[damageSpec.affinity];
+            }
+          }
           if (this.locks.has(damageSpec)) {
             continue;
           }
           this.locks.set(damageSpec, damageSpec.lock);
           const variance = Math.random() * damageSpec.variance * 2 - damageSpec.variance;
-          const difference = damageSpec.power * variance;
+          const difference = power * variance;
           // Account for variance past 0, so track if it's damage or not.
-          let amount = Math.round(damageSpec.power + difference);
+          let amount = Math.round(power + difference);
           let isDamage;
-          if (damageSpec.power < 0) {
+          if (power < 0) {
             isDamage = false;
             if (amount > 0) {
               amount = 0;