Special Equipment:

Damien owns a well-cared for Greatsword that has been handed down from father to son for four generations.
Lukis has a truly ridiculous amount of potions that he carries, including several of the more exotic healing potions, all in unmarked bottles.
Trilah uses a masterwork shortbow and a brace of very sharp daggars.


Appearance:

There are three members of Family Cohrron, and they always travel together.
Damien is the oldest.  He is a tall, muscular man, with scars from many battles.  At first glance, he seems to be a pleasant sort, but one you wouldn’t want to annoy.  Unfortunately, he gets annoyed far too easily.  He is bad-tempered except to his siblings.
Lukis is the next oldest.  He is more slender than his brother, but still quite fit.  His clothes are in much poorer repair than the others, and his face is usually haggard.  He usually has dark cirles under his eyes and his hair is always uncombed.  He doesn’t talk much.
Trilah is the youngest of the three, and the only girl.  She is a small woman, and usually mistaken for much younger than her actual age.  She is very pretty, but can be quite bad tempered, much like her brother.  While her brothers are fiercely protective of her, she very rarely needs their help.


Background:

Some said the Cohrron family was cursed.  Some said they were being punished for their ancestors’ wickedness.  Some said they were merely unlucky.  Whatever the reason, the fact remained that a terrible sickness had run in their family for an age and a half.  It was a strange disease, that caused excrutiating pain, and it crippled and eventually killed those who were unlucky enough to have it.  It was a bad way to die. 
As children, Damien, Lukis, and Trilah had watched their father slowly succumb to it.  That, it could be supposed, had been a terrible experience.  As they grew up, they spent most of the time trying to forget it.  Eventually, they more or less succeeded.  Damien became a soldier, a very good and highly respected one.  Lukis studied magic, and proved to be a natural.  Trilah, most unexpectedly, follwed her brother into the army and became a reknowned archer.  For a time, they were happy.
And then it all came apart.  Damien began to show the first symptoms of the disease that had killed thier father.  He hid it from his brother and sister as long as he could, but soon they found out.  Damien decided that he would sooner die a quick death in combat than wait for the disease to kill him.  He became a bad-tempered man, taking exception to the slightest thing, and managed to provoke many fights.  He was forced to leave the army because of his insistence that every thing should be settled by a duel to the death.  Trilah, who had always been rather bad tempered, soon followed.  It was Lukis’s idea that the three of them should form a mercenary team, because it would be significantly easier for Damien to find someone willing to fight to the death, and in the mean time, they could maybe do some good and get well paid to boot.  The other two agreed, and they did just that.  They became quite sought after and reasonably wealthy.  Lukis decided to try to find a cure for Damien.  At first, they were reasonably confident that he would find one.  But he had failure after failure.  A year passed, and then another one, and he still had no luck.  The closest thing to success was a potion that dulled the pain somewhat.  Damien had no luck either.  He bested every opponent he fought, much to his dismay.  The family’s reputation kept most of the good fighters from tangling with him; it was not uncommon for someone to surrender upon hearing that the Cohrrons had been hired.  He began to take high risks and lost causes.  He began to drink heavily, and in time, so did Lukis and Trilah.
And, inevitably, people stopped coming to them for help.  A band of worthless drunks, they said.  Have such a high opinion of themselves that they won’t take anything that isn’t likely to kill them.  Dangerous thrill seekers.  Unpredictable louts.
It was about that time that Lukis began losing his grip on reality.  His brother’s suffering and his utter inability to do anything about it, not to mention some of the more… unsavory things he had resorted to to find a cure for the disease began to slowly drive him mad. 
At the present time, Lukis while still a competent mage, could not, by any stretch of the imagination, possibly be called sane.  Damien’s condition has steadily worsened, and he only keeps fighting through a combination of strong drink, the potion Lukis concocted to relieve the pain, and sheer willpower.  He’s also become much more likely to pick a fight over any little thing, and become much more likely to become violent with complete strangers.  Trilah has also become much harder to get along with, and there are times when her brothers suspect she’s also developing the disease, which does not have what could be called a good effect on Lukis’s mind, even though she denies it emphatically.

So, in short, you have a set of three dangerous mercenaries, one of which has every reason to get himself killed, one who is half-mad, and one who may also be trying to get killed, or could just be a b**ch.


Roleplaying Notes:

Just to clarify: Damien has the disease, Lukis does not (so far), and Trilah might.

The more dangerous something is, the more likely they are to do it.  They might make particularly good henchmen, because what could be more dangerous than opposing the heroes?  Of course, this does not mean that they have no ethics; they may join a villain and try to sabotage him (whether or not they try to get caught at it I leave as an excercise to the GM.)  Damien or maybe even Trilah may pick a fight with the PCs, and insist on a duel to the death.  If they end up killing Damien, if you feel evil, have the other two swear vengance.  If you feel nice, have them thank the PCs.
It is possible that the disease progresses so far in Damien that he is crippled by it, although this would probably result in him committing suicide.
The disease is extremely painful, and might possibly warrant bonuses to the PCs in fighting Damien and Trilah if she also has it.  Lukis is half-insane, and this could also result in bonuses to the PCs.  Of course, it could also result in penalties if madness simply makes him a more effective mage.