It’s a tired old cliché, but let’s face it: from time to time, everyone is going to make a character with no living relatives and no ties to anyone or anything. While some GMs will frown on deliberately distancing oneself from society in this fashion (not to mention all the plot hooks that a family could potentially provide), it’s entirely possible to make a detailed and nuanced backstory that happens to involve a lot of dead relatives. Here are a few starting points, many of which include some plot hooks of their own.
1. A Terrible Curse. When you were still a child, one of your parents did something to attract the wrath of an evil witch or warlock, who cursed not just the offending parent, but your entire family. Every three years to the day since this occurred, the oldest member of your family is struck dead under unusual circumstances, and you are next in line. You adventure in search of a way to lift the curse, or perhaps to slay the one who laid it upon you, which may or may not be enough to break its hold.
2. Executed by the State. Your parents were members of a rebellion, and when you were still just a few years too young to participate, they were captured during a mission, after which they were labeled as traitors against the state, tried, and, ultimately, executed. Any siblings you may have had gave their lives for the rebellion as well, though not necessarily at the same time. You may or may not have been taken in by a family friend and member of the rebellion, who may also, ultimately, have met the headsman, or may simply have died of old age. If the rebellion still fights on, you may be moved to join them, or may blame them for your family’s demise. Another possibility is that your family is alive, but imprisoned.
3. Disowned. Your family isn’t actually dead, but as far as they’re concerned, you are. There are all sorts of reasons why you might have been disowned by your family: you could have committed a crime or heresy they could not forgive, you could have married someone they did not approve of, or you may simply have failed to live up to their standards and proven to be an embarrassment in their eyes. Perhaps part of why you adventure is to redeem yourself in the eyes of your family.
4. Adopted Immortal. Elves, dwarves, and the like aren’t actually immortal, but as far as their lifespans compare to those of humans, they may as well be. You were adopted by a human family under mysterious circumstances, and lived a full and happy life with them, perhaps even taking a spouse and having children. After 100 years, all of these people have died of old age, but you’re still in the prime of your life, and, unable to bear living in the same place now that everyone you truly cared about has moved on, you have turned to adventure. Whether or not you actively seek your birth parents, and the reason for your adoption, is up to you.
5. Shipwreck. Your family was on a sailing ship that was struck with bad weather and wrecked in the ocean. You were lucky (or skilled) enough to make it to shore, but it seems that the rest of your family wasn’t so lucky. The ship carried everything that your family had to its name, and so, penniless and alone, you turn to a life of adventure to make ends meet. Of course, without any corpses, there’s no saying for sure whether some of your family may still be out there, somewhere.
6. Disease. Plague was a real threat in medieval times, and it’s estimated that the Black Death killed between one third and one half of the population of Western Europe when it hit. A similar plague struck the area from which you hail, and your family was particularly unfortunate, with only you managing to survive. It’s possible that you blame the local authorities for improperly handling the plague, or the loss may have caused you to seek solace in religion—or else in bitterness and drink.
7. Death by Mob. This option works best for unusual races, but can potentially apply to humans as well. You were brought up by only a single parent, who was always shunned by the locals, and forced to live on the edge of town, either due to his or her own unusual appearance, or because of yours, and whispered rumors about who your other parent might have been. When you were nearing adulthood, a series of bad crop yields led to a witch hunt, for which your parent was ultimately blamed and killed by ignorant and superstitious townsfolk, leaving you with little choice but to flee for your life.
8. Summoning Mishap. You were raised by a single parent, and never knew the other. Your parent was an accomplished spellcaster, and when you were nearly of age, a summoning ritual involving a fiendish entity went awry, resulting in your parent’s death (or perhaps imprisonment on the lower planes). You barely escaped with your life, and made a lifelong enemy of the fiend in question. The experience may have drawn you to master what your parent could not, taking up arcane magic, or it may have turned you off the stuff entirely.
9. Assassination. You lived a normal, quiet, happy life with a seemingly normal family, until one day, when you were almost an adult, assassins struck your quiet home, killing everyone there. You escaped through happenstance, either because you were away at the time for some unexpected reason, or because you just happened to get a glimpse of them in time to find a good hiding spot. You have no idea why anyone would want to kill your family, but you’re sure going to try and find out.
10. You Killed Them Yourself. As an adventurer, you don’t necessarily think much before running something through, and that kind of instinct may very well have been in place well before you took to your current career. Whether your character is just so evil he would literally kill his own mother for a few gold pieces, or if the deed was done in self defense against an abusive parent, or due to even more tragic circumstances, the blood of your family is on no one’s hands but your own.