Dungeons and Dragons - Creating the Ultimate Arch Nemesis

As a dungeon master, once the adventuring party start campaigning through higher levels, from the eleventh level and upwards, it is time to provide some interesting challenges for paragon level play using fourth edition rules. On exciting way to move the story along and deepen the overall plot for your campaign is the introduction to your arch villain.
This makes it much more interesting for your players as well. They have cut their teeth on saving villages from destruction, delving into kobold infested dungeons and bashed a few errant trolls.

Now your adventurers need an ongoing thorn in their side.
Someone, or some thing operating behind the scenes or if you prefer, become directly involved and often with confrontation with your adventurers.

When I last played the game as a member of a party, I was a 14th level mage with a penchant for fire.
Also in the party were a cleric with a huge sharp mace, a dwarf with a continual running nose, a fighter with a short temper, an elf that was short for his race and a barbarian seeking to regain his ability to rage (he was cursed).

The party averaged a level of 14th to 16th. We were tasked with bringing a component of unknown origin to a priest to a temple in a city we were familiar with.

The creature that provided us the task was an agent of goodness and light and also a servant of a demi-god. We had dealt with this creature before and on this occasion we needed to complete the task with much haste as the object over time would be dangerous to us all (we did not know it then, but it was part of an artefact created by a immortal being that was deadly to mortals given sufficient time to exposure).
On our journey to the city, we were accosted by a supernatural being at night.
In the ensuing battle, we were all fairly hurt and our fighter with an attitude lost his head, and we lost the artefact. The player who was the fighter class wanted to generate a new character so losing his head became part of the plot.

Once we had reached the city and found the priest, we relayed what had happened the previous night.
We were told we had encountered an agent of a dark demi-god, known only as Nemesis, who we eventually found out later in the campaign was an undead monk.

Over the course of many gaming nights, we would encounter Nemesis from time to time and on occasion it also had minions used against us and the battles were many, Nemesis would win some, and we would survive others.
Ultimately the adventurers were able to finally and permanently defeat it (much to the chagrin of our dungeon master). With creating your arch fiend consider the following attributes • Make your fiend 3 - 5 levels higher than your highest levelled adventurer• Consider your villains overall goal, such as domination of a nation, destruction of the adventurers for a previous transgression or as an agent for a higher power.• Make the nemesis a unique character in itself, what if your party is up against a necromantic beholder, a lich mind flayer, a human general with delusions of grandeur or even a vampiric troll?• Allow enough information to flow to have your major villain have the adventurers jump through hoops, setting up the party to be constantly teases enough to find the enemy, yet the enemy always seems one step ahead.• Does you villain have a major powerful weapon, or a unique set of armour, or a gem with valuable abilities? Consider a major object that helps and enhances your villain's abilities or tasks.
• Minions, does your nemesis have minions, or is it one that prefers to work alone, or have others do it's bidding for a time for money.• If he or she always on the move, never living in one place for long, or does it hold a lair, or dungeon, or deep cave, or even hold a village in thrall?• Give your character interesting traits, is he or she quick to anger, or have obsessive compulsions like always making decisions on the toss of a coin, or loves to leave written messages taunting the party.• Your arch rival is ruthless, cunning and smart, you as the dungeon master know the strengths and weakness of the adventurers, but don't make your rival omniscient.
A good villain has a back up plan, and also knows when to cut its losses and high tail it out of there.
It may take some time to develop your super villain, and over time, your villain progresses as much as your party adventurers do, for your campaign, lead your adventures to a final conclusion.
Everybody will be in for one heck of an enjoyable time when the final conflict arrives.