Corrupted vs Cursed Magical Items: Why You Should Always Add A Backdoor

In this article, I will attempt to make a case for what I like to call, Corrupted magical items. Let's start off with some definitions that I will be using throughout. 

Cursed Items 

To me, a cursed item is a magical item that someone from the party obtains, either by accident, or by intent of an NPC. This magic item will typically grant a nice bonus to something, at the cost of another skill. In addition to this trade off, the cursed item will usually be a quest to get rid of the item. 

 Example:  

Cursed Dagger of Danzig 

This obsidian dagger grants +2 to Attack and Damage rolls, however, the dagger will occasionally yell "Mother!", or some other incomprehensible gibberish. 

Picture the party's rogue sneaking ahead of the group, on a mission to quickly and quietly subdue the lone guard outside of the bandit's den. Just as the rogue makes her final approach, one hand outstretched ready to cover the guard's mouth, the other hand on the dagger ready to slit their throat. Suddenly, the otherwise quiet night is punctuated with, "TELL YOUR CHILDREN NOT TO WALK MY WAY!" screaming from the cursed dagger. The gig is up, the rogue's been had, no more element of surprise for the party. After the party narrowly defeats the bandit leader, the rogue decides to cast the dagger into the sea, then retire for the evening. When dawn breaks, the rogue finds the dagger and sheath back on her hip, right where it's happy and content. 

Given this example,  it's important to point out, the player is aware of this curse. Perhaps when they found the dagger, it was singing away, stuffed in a bag somewhere. 

Corrupted Items 

A Corrupted item is one that offers immense power, at a seemingly good bargain. The tradeoff between boon and bane appears minimal, and, "Is probably just there for flavor...". These items would typically come mid-game (assuming you're running a campaign to get the players to level 20 or beyond, this item would come in at level 12 or so), and would offer a fairly overpowered bonus, and a minor oddity that comes with it. 

Example: 

Robes of the Balding Wizard 

These robes grant the wearer two additional 3rd level spell slots, and grant +3 to spell attacks. While wearing these robes, the wearer is considered Undead. 

Picture the party's wizard, living it up, slinging fireballs like he's the Wolf of Fireball Street. The party's favorite tactic for clearing out a dungeon – the tank opens the door, the Wizard casts fireball, they close the door, celebrate. This has worked really well for the party so far, they're just about done with the dungeon, just the boss left, and they decide to take a long rest, because that's what murder hobos do... They finally ready for the boss fight, the tank opens the door, the wizard begins to cast fireball, his eyes go white, then drops a fireball, centered on the party... Wait, what? How? What do you mean?  

Remember that line on the magic item that says, "While wearing these robes, the wearer is considered Undead"? Yeah, that line. That's how, that's why. The boss used Control Undead, or some Legendary/Lair action to seize control of the wizard. It's nasty, but the wizard has been getting plenty of use out of those robes. It's time to pay the ferryman.  

In the example with the wizard, it's a great boost to a single player, with a minor flaw that can easily be exploited by a DM playing the long game. If the party feels like they are unstoppable, stop them. 

Both of these types of magical items have their place at your table, I highly encourage you to find different ways to use this concept to screw with your party.