What's In a Knife?
When writing a character's back story, it's important to include a certain number of "knives". Knives are essentially anything that the DM can use to raise the stakes of a situation for your character. Anything that can make a conflict personal, like a threatened loved one or the appearance of a sudden enemy. They're called "knives" because the players lovingly forge them and present them to the DM so that the DM can use them to stab the player over and over again.
Credit & Source
A Good Knife Block
When building a back story, your players should give you 7 - 12 knives. There are a variety of knives your players can give you. Here are some examples:
- A named person your character cares about, living or dead (e.g. sibling, spouse, childhood friend)
- A phobia or trauma your character has experienced
- A mystery in your character's life (e.g. unknown parents, unexplained powers)
- An enemy your character has
- Any ongoing obligation or loyalty your character has
- An obligation your character has failed
- A serious crime your character has committed
- A crime your character is falsely accused of
- Any discrimination experienced (e.g. fantasy racism)
- A favored item/heirloom
- A secret your character is keeping
Conveying to Your Player
Below is an example of how to present this to your players. This should give them a good understanding of what the intent is, and what they need to do.
In order to make the campaign we're about to embark on compelling for you and the rest of your party, I as the DM need you to provide me with a background story that I can interweave into your adventure. To accomplish this, I need you to give me 7 - 12 knives. Yeah, I said knives.
Any part of your back story is considered a knife. These knives will be used to integrate your character into the world and get you invested in the story. I may break your knives into smaller, sharper knives with which to stab you. Or I may bundle different characters' knives together into one GIANT knife. Because we're all secretly masochists when it comes to D&D, the more knives you give me often means the more rewarding our story will be.
On the other hand, you don't want to be a sad edgelord with too many knives. A butt-load of knives just means that everyone in your party will inadvertently get stabbed by your knives, and eventually that gets annoying.
Oh, and give me some variety. All of your knives shouldn't be family members, nor should they be crimes that you've done in the past. That's a one-way ticket to repetitive game play.
Each knife should consist of no more than two well worded sentences. I don't need a full page write up of each one. That's my job.