Obviously, you can’t have your level 3 PC getting a hold of a legendary artifact of immense power. But that also should not stop you from putting these items into the game. Legendary items can add a lot to a game world. Here are some ideas to keep posessions like these out of PC hands.
1) Make it hard to get.
The fastest way to keep PC’s from getting these Items, is to make them impossible for low level characters to obtain. Maybe it has an insanely powerful guardian spirit watching it, maybe it has an entire guild protecting it, or maybe it simply cannot be reached without six consecutive Fly spells.
One way or another, you can make these items impossibly out of reach by low level PC’s by simply making them hard to get
2)Add a prerequisite to the powers of an Item.
Legendary items are designed for legendary characters. Think about it. A novice wizard would never know how to use a wand of city destruction. The Legendary Helm of Devotion would never work for a character who has done nothing for his patron deity. Even a fighter would have to have a certain amount of experience with enchanted items and weapons in order to use the abilities in Doombringers’s Legendary Sword of Death
Simply stated, make a character level prerequisite for your Item of Legend abilities. As a Novice, your character has a +2 longsword. As an Adept, it acts as a +4 flaming sword. As an Expert, it acts as a +6 Flaming Sword that grants a Wall of fire three times daily. As a Grand Master, your sword’s full power is unlocked, making it a +8 Vorpal Flaming Sword that deals damage again the round after it hits, can cause a ring of fire to surround you three times a day, and has a 20% chance of automatically killing a stricken foe…or…well you get the idea.
This is, in my opinion, the simplest and easiest ways of regulating Legendary Items in PC hands.
3) Have their Patron Deity take it away and replace it with something more reasonable.
Although this only works for clerics, paladins, and the like, this is a handy little way to regulate a PC’s power.
At night, give the Cleric a Vision where his/her deity speaks to them telling them that the item is needed elsewhere, and that they will be rewarded for the sacrifice. When they wake up, the Legendary item is gone, and in it’s place is another item that is closer to the PC’s level.
As a suggestion, I recommend that the item be very strong for a character of that level so that they don’t feel quite as cheated, but still keeping the item within reason.
4)Make the Item Radiate with Power when held or equipped.
If you think that Legendary items should have Legendary effects on everybody who uses them, and your characters aren’t Clerics or Paladins, then make them radiate with power visible to everybody, anywhere nearby.
This is not quite as clean as some of the other options, but it will certainly do the job. Suddenly, upon equipping the item and walking into town, it will become widely known that a legendary artifact is being worn by such-and-such in whatever town you have them in. Suddenly, your PC’s will find themselves on the wrong end of Adventurers who are much stronger than they are, seeking the Legendary Item that they have.
The first few encounters should be higher level encounters, but with the legendary item, overcomable. However, each encounter should get progressively harder, to the point where they are completely outmatched against superior foes.
By the same rule, they would have an impossible time selling the item. If they go to a market small enough to sell it safely, then nobody will be able to purchase such a powerful Artifact. In any market with enough money to buy it, a much higher level thief would take it before they got within fifty meters of a shop.
Even in a remote area, they might find themselves bombarded by Clerics or Paladins who have been told in a vision by their Gods to go and retrieve the item. Certainly some of the minor deities have uses for such things.
5)Anyting else you can think up
With these tools in your belt, you should be able to stop PC’s from getting their hands on that Legendary Amulet of Powergaming, however, this article is neither the Alpha nor Omega of DM tricks. There are plenty more out there. Use them all, and good luck