diff --git a/constructors.js b/constructors.js
index d0bf11a..12a0ead 100644
--- a/constructors.js
+++ b/constructors.js
@@ -10,7 +10,11 @@
  * @property {string} description
  * @method   printDetails
  */
-
+  function Spell(name, cost, description) {
+    this.name = name;
+    this.cost = cost;
+    this.description = description;
+  }
   /**
    * Returns a string of all of the spell's details.
    * The format doesn't matter, as long as it contains the spell name, cost, and description.
@@ -18,6 +22,9 @@
    * @name getDetails
    * @return {string} details containing all of the spells information.
    */
+    Spell.prototype.getDetails = function () {
+      return "You cast " + this.name + " which cost " + this.cost + " and does " + this.description;
+    };
 
 /**
  * A spell that deals damage.
@@ -43,6 +50,11 @@
  * @property {number} damage
  * @property {string} description
  */
+  function DamageSpell(name, cost, damage, description) {
+    Spell.call(this, name, cost, description);
+    this.damage = damage;
+  }
+  DamageSpell.prototype = Object.create(Spell.prototype);
 
 /**
  * Now that you've created some spells, let's create
@@ -60,6 +72,12 @@
  * @method  spendMana
  * @method  invoke
  */
+  function Spellcaster(name, health, mana) {
+    this.name = name;
+    this.health = health;
+    this.mana = mana;
+    this.isAlive = true;
+  }
 
   /**
    * @method inflictDamage
@@ -71,6 +89,13 @@
    *
    * @param  {number} damage  Amount of damage to deal to the spellcaster
    */
+    Spellcaster.prototype.inflictDamage = function (damage) {
+      this.health -=damage;
+      if (this.health <= damage){
+        this.health = 0;
+        this.isAlive = false;
+      }
+    };
 
   /**
    * @method spendMana
@@ -81,6 +106,14 @@
    * @param  {number} cost      The amount of mana to spend.
    * @return {boolean} success  Whether mana was successfully spent.
    */
+    Spellcaster.prototype.spendMana = function (cost) {
+      if (this.mana >= cost){
+        this.mana -=cost;
+        return true;
+      }else{
+        return false;
+      }
+    };
 
   /**
    * @method invoke
@@ -108,3 +141,22 @@
    * @param  {Spellcaster} target         The spell target to be inflicted.
    * @return {boolean}                    Whether the spell was successfully cast.
    */
+    Spellcaster.prototype.invoke = function (spell, target) {
+      if (!(spell instanceof Spell)){
+        return false;
+      }
+
+      if(spell instanceof DamageSpell && (!(target instanceof Spellcaster))){
+        return false;
+      }
+
+      if (this.mana >= spell.cost){
+        this.spendMana(spell.cost);
+        if (spell instanceof DamageSpell){
+          target.inflictDamage(spell.damage);
+        }
+        return true;
+      }else{
+        return false;
+      }
+    };