Fallen Heroes
Heroes can make the best villains?
Well, okay, being a hero and a villain at the same time is impossible (in the world of d&d maybe) for a sane character. But a few things are as chilling as a villains who used to be a hero (like the death knight in war craft 3). And fear can be a villain's best friend. There are a number of ways to use the fall of a character in a story. For starters, there's the now classic bit where the epic adversary is revealed to be a former hero in his own right. How do the heroes/readers react? Can they redeem him/her, or must they destroy this former champion of good to save all that they love? Or, if you're playing villains, can you trust this former hero? Will he turn on you? Is he even really a villain now? Unlike a lot of people, this character has every excuse to have an undetectable alignment at all times. Sure, it's hard to trust a lot of villains, but at least you know they won't be selling you to the heroes without some serious guarantees. And even if he's really as evil as he claims, that just means you know you can't trust him. After all, this is a guy who betrayed the heroes.
Here's another possibility. If something has gone tragically wrong, and the heroic alliance has given in to the master villains, instead of the end, it could be the beginning of a new twist.
What do the former heroes do now, in the service of their dark master? Or, for that matter, do they decide that reigning in Hell is better than serving it?
The most obvious way to use this in a story, however, is by starting with villains who used to be heroes. The evil prestige classes in the DMG (that a dungeon masters guide for anyone not into d&d) can be especially helpful in this case. This offers some of the unusual flavor of the evil campaign while maintaining more traditional adventuring elements. While the characters are now evil and have their own plans for power, conquest, immortality or what have you, they area also adventurers. You may well want to fall back on your old skills to gain gold, magic and power. You might also be able to work with old contacts for as long as you can hide your change of heart. However the idea of the Fallen Hero comes into the campaign, the most important question to ask is why. What has convinced a hero that was a lie? Villains can be terribly persuasive, but the vast majority of heroes ignore their sensible explanations and wade in, swords or spells flying. Why did she listen, when most other heroes wouldn't?
SOME POSSIBLITIES INCLUDE:
Betrayal: If someone abandoned the hero at a critical moment, the experience may have shattered his faith in good might be shattered. This is especially true of heroes who place great stock in trust between friends. A villain who recruits such a former hero might find him short on loyalty and honor, but long on rage and pain. Fallen heroes of this type make good throwaway weapons, but rarely have staying power. The few that manage to give endurance to their bitterness are utter terrors as enemies, as they have given up hope for hate. They rend to be chaotic evil, driven as they are by fury and madness, but can be a clever villain can coax them into any evil alignment.
Broken: Even heroes have their limits (perfect example Marlin Brando in Apocalypse Now). If a villain has enough time, patience, and sheer ruthlessness, he can simple torture the hero into submission.
This is a very risky scheme, of course. Even if the hero doesn't escape, other heroes are likely to come charging in to the rescue. On the other hand, a broken hero is highly unlikely to turn against the villain for a long time, if ever, without help from other heroes. Broken heroes tend heavily towards lawful evil, severing the master without question. On the other hand again, somewhere beneath the fear and subservience is likely to be a sort of hatred, and if the enslaved former hero can kill the villain, there may a new warlord (or any evil being) in charge.
Cowardice: While this isn't a likely fate for a true hero, some more neutrally-aligned adventurers aren't as brave as their comrades. All it can take is one moment of failed courage to push someone teetering on the edge into evil. Such a 'villain' probably isn't very villainous, having decided to be worthless rather than aspire to anything, but is both dangerous and unpredictable. A Fallen 'hero' of this variety is likely to be neutral evil, only looking out for them selves.
Love: Love isn't just for heroes or villains. Opposites attract, and a great hero and epic villain are as opposite as it's possible to get. While many such affairs and in tragedy, sometimes one character decides to make the leap and join the beloved on the 'other side'. While, annoyingly, this usually results in a villain's conversion to good, occasionally a hero will make the 'sacrifice' of becoming a villain. Fallen heroes of this type tend to be the same alignment as their beloved, but both villains tend towards lawful evil. Villains can love, but even evil characters require trust to love.
Magic: There are plenty of ways that evil can be forced on a hero in magical world. The infamous helm of opposite alignment is the best-know method to turn a hero into a villain (only applicable to d&d strangely enough, unless your story somehow justifies the helm of what not...), but there are plenty of other ways of literally changing a hero's mind. The problem with this sort of 'Fall'' is that it's artificial. Heroes and deities tend to be very forgiving of this sort of thing, so long as the forms are followed when the 'victim' recovers. In the meantime, however, the new villain tends to embrace evil as completely as a hero cherishes the ideals of good. Alignment is usually the exact opposite of the former hero's, though a powerful villain can heoretically force any alignment on a hero.
Revenge: Revenge can create heroes, but the powerful emotions engendered by wanting to destroy one's enemies are so easily nudged into more throughly evil impulse... at the right moment. A hero driven to kill 'the enemy' might find that other villains don't sound as misguided as they used to. In fact, a villain who can deliver the most trusted ally possible is a Fallen hero. Such heroes tend to be lawful evil, never quite accepting the idea that they've crossed the line. They maintain fragments of the old code of honor but are willing to do things that would make 'real' heroes ill.Welcome to the dark side.