So you’ve finished your story and edited it and now you look at your ending. Is it a final ending or an open ending? Meaning is this the end for the characters or will they be returning. This will depend on a couple of factors.
First is your story a self contained entity. Will your group of heroes be going on other adventures, or will they ride off into the sunset and have no further adventures? If you are not sure if you want to write with these specific characters again, then leave it open. So you vanquish the villain and your heroes have won the day, you don’t have to write them into oblivion or into any set future. You don’t have to set their destiny don’t tell your reader that they’re going to become a king or anything of that nature or if you do, remember the Conan films. They tell you that “Conan went on many adventures and eventually found his own kingdom, but that is another story” and there you have it. We know what will happen to Conan but there are still plenty of adventures to be had until then. Or my personal recommendation is to leave the characters that interest you alive and leaving the scene of the recent adventure. You can pick up with the character later and with a few sentences connect this character as the same that you previously saw. Detective stories tend to due this more than most other genres. They will tell a little about the main character and his last adventure by referencing something in the office or a memory associated with a specific place. And you still have your character to evolve on his many adventures.
Secondly, if you kill them leave them dead. Like all rules there are exceptions to this, Sherlock Holmes, and Dracula being two well known examples. If you can write a character back in a manner that is believable and well done, then by all means continue their journeys. Most of these resurrections are found in science fiction or horror but there are times that an author will merely bring back a dead character never mentioning the method of resurrection or that the character was believed dead at all. So if you are going to end a character and I mean truly end a character (i.e. kill them) do so with good reason, and make sure it’s a character you don’t mind killing. Unless of course resurrection is a common theme in this new world you’ve created or it is an integral part of the story. Pirates of the Caribbean film trilogy being a good example. They killed Barbosa in the first film, then brought him back in the second film only for Jack to die in the second film and bring him back in the third. This they tied together why Jack was needed and how it was going to be done, and with all the other “mystical” things that are intertwined within the movie it was fine. Likewise, Dracula is a vampire, so you don’t have to show how he came back to life every time. May I suggest barring supernatural entities or epic adventures with magic be wary of killing a character or do as Arthur Conan Doyle did and make sure you bring them back in a method that is fitting with the character. Let’s say that you have a cowboy who rides into a burning barn to save some cattle and only his horse rides out of the barn an empty saddle on its back. Well you’re other characters may believe him to be dead, but he could have gone out the back because he didn’t trust his partners or to get the jump on the man following them.
The main point I’m trying to get at is don’t paint or in this case write yourself into a corner where you are forced to do something far fetched and out of tune with the tone of your work. That said, happy creating and remember you can kill them all, but it’ll make a sequel a little bit tricky.