diff --git a/constructors.js b/constructors.js
index d0bf11a..df451a0 100644
--- a/constructors.js
+++ b/constructors.js
@@ -11,6 +11,16 @@
  * @method   printDetails
  */
 
+function Spell( name, cost, description ){
+   this.name = name;
+   this.cost = cost;
+   this.description = description;
+}
+
+Spell.prototype.getDetails = function(){
+   return this.name + ' ' + this.cost + ' ' + this.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.
@@ -44,6 +54,13 @@
  * @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
  * `Spellcaster` objects that can use them!
@@ -61,6 +78,13 @@
  * @method  invoke
  */
 
+ function Spellcaster(name,health,mana){
+   this.name = name;
+   this.health = health;
+   this.mana = mana;
+   this.isAlive = true;
+ }
+
   /**
    * @method inflictDamage
    *
@@ -72,6 +96,14 @@
    * @param  {number} damage  Amount of damage to deal to the spellcaster
    */
 
+   Spellcaster.prototype.inflictDamage = function(damage){
+      this.health -= damage;
+      if(this.health <= 0){
+         this.isAlive = false;
+         this.health = 0;
+      }
+   };
+
   /**
    * @method spendMana
    *
@@ -82,6 +114,15 @@
    * @return {boolean} success  Whether mana was successfully spent.
    */
 
+   Spellcaster.prototype.spendMana = function(cost){
+      if(this.mana >= cost) {
+         this.mana = this.mana - cost;
+         return true;
+      } else {
+         return false;
+      }
+   };
+
   /**
    * @method invoke
    *
@@ -108,3 +149,23 @@
    * @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 === undefined || spell === null) {
+         return false;
+      } 
+      if (spell instanceof DamageSpell && target instanceof Spellcaster) {
+         if(this.spendMana(spell.cost)) {
+            target.inflictDamage(spell.damage);
+            return true;
+         }
+      }
+      if (spell instanceof DamageSpell && !(target instanceof Spellcaster)) {
+         return false;
+      } else {
+         if(this.spendMana(spell.cost)){
+            return true;
+         }
+      }
+      return false;
+   };