Recurring antagonists

Recurring antagonists are essential in story telling as they oppose the PCs.
Their recurring nature creates a connection between them and the PCs which leads to a better story.

Darth Vader by Andres Rueda

An encounter at its most basic is PCs vs. monsters
with all the monsters dead at the end of the encounter.
In my experience, PCs tend to stop a fleeing monster
so that they can't alert other monsters or return in a future fight.
This makes it harder to keep recurring antagonists alive.

Role Playing

An antagonist the PCs know directly or indirectly
introduces more role playing opportunities.
There needs to be a connection between the PCs and the antagonist.
It gives an antagonist more back story, motive and mannerisms.
This makes his final defeat more satisfying.
However, fighting the same exact monster 5 times in an adventure
hardly seems fun.

A cardboard evil villain who is evil just to be evil should be avoided.
An antagonist should have a background, goals, etc, in other words he should have depth.

Indirect impact

The antagonist has a past, enemies, friends, minions, etc.
These elements express his character traits, his reasons for what he does, how he treats his friends and foes.

All of this information can be spread out over the course of an adventure:

• The past can be ruined villages, killed opponents, how others feel about his past actions, etc.
• How he treats his enemies says a lot, the PCs can witness those enemies first hand.
• How he treats his minions and why they follow him (loyalty, fear, money, love, blackmail, etc.)
• Are there people the antagonist cares about? Who are these people and why does he care?
• Capturing or killing allies of the PCs
• Destroying places or buildings the PCs care about

The antagonist acts himself or through his minions,
either way the PCs get to know him without ever meeting him.

These indirect interactions are often overlooked in building a connection between PCs and an antagonist.
This information is shown multiple times to the players so they remember and it is shown and not told in an info dump.

Direct impact

Keeping an antagonist alive shouldn't be forced, I prefer to give the PCs situations and NPCs and see what happens.
When put in direct combat, PCs are amazingly effective at preventing opponents from fleeing and killing antagonists.

In my opinion fudging dices to save an antagonist is not recommended. Players mustn't think that an antagonist is destined to survive no matter what they do.

There are many ways to keep antagonists alive:

• Fleeing possibilities: teleport, minions keep PCs busy, multiple clones, illusions, mist form (vampires), simulacrum, etc. This can work once per antagonist but may get annoying.
• No body was found: antagonist falls of a cliff, gets sucked into a portal, is in a big explosion, etc
• They are more valuable alive than dead, by providing information, fighting against a common enemy, etc.
• PCs can't even fight the antagonist directly because of power difference, public image, etc.
  The antagonist can be powerful in battle, have much influence or an army.
• PCs don't think of him as an antagonist, he/she may even be an ally. He may be deceiving the PCs or truly is their ally but with opposing goals which eventually turns him/her against the PCs.
• Immortality: lich, discorporation (gods), etc.
• Getting raised, returning as an undead or some other form after death.

The antagonist impacts the PCs even if he dies:

• he is part of an organization, he has a boss.
• he has a powerful family member that wants revenge.