I wanted to add that folks keep commenting about CHEKOV'S GUN. But I should clarify something since lost of folks are conflating the two. Since knives are OPTIONAL tools for the DM, they are essentially the opposite of Checkov's gun; which is a statement about paying off ALL set-ups. The gun MUST be fired.

Knives are about optional tools you give away in the hopes that SOME of them MAY be useful. The two while sharing a couple of similarities they're not the same thing and their core principles are polar opposites.

OP here!! Great video (and INCREDIBLY flattering, I am going to try not to let "best reddit post in RPG history" go to my head). I love the way you expanded on it, and explained things I didn’t fully flush out in my post. The concept of having so many knives so that the DM has a variety to choose from that best fits the story is EXACTLY where I was going with it!

I'm so happy that the idea has been useful to so many people!

Ironically, "I come from a happy family and now I am setting out to see the world" IS still handing over a knife: The happy family! The most knife-less characters I usually run into are ones solely motivated by money but it's also the archetype most prone to making knives during the game.

I feel like,  when crafting knives, you need to ask yourself "What's the point?"

The point is where the stabbing happens

I’ve been using the knife analogy w my players for a while now tho I will contrast it with Sandcastles, as in, “is this piece of backstory a Knife or a Sandcastle?”
Sandcastles are “I’ve put thought and emotion into this and if the DM came and stomped it I’d be miffed” and can be for players that are knife-shy — I’ll usually try to build onto a sandcastle, or just bring it in so the player can show it off when they need a lower-stakes moment.

"What are you going to do, stab me?"
-Guy who just handed his DM 5-10 knives

One important caveat to "knife theory":  not every player thinks the most interesting way to incorporate backstory elements is ways to have things happen to hurt their character (despite the knives and stabbing language).  I've been running TTRPGs for over 20 years now, and almost every player I know who writes character backstories that make their character a loner with absolutely zero "knives" (family already dead, no friends, hometown already burned down) is a player who's been burned by previous DMs who saw character backstory elements exclusively as ways to hurt the character to "add drama" (like literal knives) and nothing else and is now preempting that unpleasant process by stabbing their character with and breaking every single knife inside of their backstory.  If you, as a DM, want your players (especially those players) to be comfortable handing you knives, you have to see them not as knives to stab the PC with, but as tools.  Sometimes you can use a backstory element to hurt the character by "stabbing" them with it, but it should be occasional.  They should also come up in neutral, or especially positive ways.  If you want the PCs in your game to have friends that you can imperil, you need to have those friends be people they get help from!  Make the friendship feel real, have it be a mutual relationship where they do things for each other.  If there's positive payoff as well as negative, the player will be a lot more comfortable forging knives for you, because they know you aren't inevitably going to use those knives to stab them where it hurts.  Odds are just as good that you're going to use the knife to cook them a delicious meal.

It's very easy to misuse "knife theory", especially if you take the name too literally, and produce players who end up playing murderhobos with no attachment to the setting.  I've had to help out a lot of players like that over the years.  Hell, I ran World of Darkness for years, and it has a Merit you can buy whose sole effect is "This is an NPC who is genuinely in your corner, they will never betray you (unless you betray them first), and the GM will not kill them off for cheap drama".  I consistently ban that merit, not because I want to kill off their friends and allies, but because I have better ways of using those connections to produce drama and story fodder than by stabbing them with "your friend betrays you/is killed by the bad guy", and I refuse to tax the players with a resource they're meant to use for actual benefits to ensure that I don't do that to them.  If you want this character to be your true and genuine friend who will never betray you and who I will never kill without doing it onscreen where you have a genuine and proper shot at preventing that, just tell me and I'll do it for you.

Today I learned a knife is the inverse of of a hook.
DMs present hooks to players. Players can present knives to their DMs.

I really love this gag of creators making cameos in each other's videos, it warms my heart to think about these People being friends.

Lo, and behold. They were knife ear-rings! Looks like I was misremembering them being swords!

Fun fact: This doesn't just stick to DND. Or TTRPGs/RPGs. This extends to any character making. That one oc stuck in your brain that has no depth? Use this. That one book character that has no motivations, goals, or life? guess what.

I'm more likely to give my DMs knives to hurt my character than to give that character a name!

The other side of this, I think, is that the players should be able to declare stuff off-limits. If you want your character to have a spouse or a family but you don't want them to die tragically to motivate you or get taken hostage so the party takes the villain seriously, the GM needs to be open to that too. I've definitely seen players tell me they're sick of playing tragic sadbeans or murderhobos so they want a home life to go back to between adventures, but please don't do more than lightly interact with that aspect of the characters. When that happens, you should respect that request, but I do also think it's fair to respond by asking the player to make a knife or two unrelated that you can use instead.

Knives are a great way to “chase your players up a tree”. They give you some levers to pull to get your players to be even more engaged in your campaign.

I once had a player playing a centaur in our multi-year campaign. Their “knife” was that they were a human turned into a centaur by an amateur wizards spell-gone-wrong. Toward the end of the campaign, that player’s boyfriend (who had never played D&D) joined our group and I had him play that very wizard!

It was a great way to add a little bit of tension within the party and gave the new player an opportunity to roleplay someone trying to correct his mistakes from the past.

4:19 me every night trying to sleep:

Another good way to visualise this is the "no strings attached" saying, but trying to do the opposite. Go through your character's life and attach a string to every major event or phase that the DM can pull at. Instead of just "living there for a time and moving on" make them move on for a reason that can catch up to them. Instead of "doing the job and going separate ways, no strings attached" - absolutely attach some strings.

That's the part that can feel counter intuitive, feel like working against your character, creating obstacles for yourself. That takes some psychological breaking into, and some trust falling with your DM, but is absolutely worth it.

3:00 And the ultimate "set of knives", the lazy "I have amnesia" backstory.  Anything can come back to haunt you and you won't even remotely be expecting it.

Been using this idea for ages without a term for it.  My one caviate is an excess of knives doesnt make you an "edgelord". You can be an edgelord with 1 or even no knives. An excess of knives results in you feeling disjointed from the party. If you have all these unresolved problems why are you tackling the main adventure?

If a player wants that personalized content, but their backstory is bare, poke them with questions. "Oh, you're a fighter! Where'd you get trained? Joined the army for a bit, you say? That's a pretty short stint, did you desert? What was your officer's name, and did they like you? Any war buddies? Who'd you fight against?". They might not be good at inventing something out of whole cloth, but they might do better with your prompting.

Or you can have them roll for a backstory, as there are plenty of frameworks for that out there, and then sink your teeth into what they conjure. "Okay, the chart says you started wandering because you got inspired by the town bard in your small hamlet, then you got mugged by bandits and forced to become one before escaping, and then found a belt that's not magical but has runes you can't read. I've got like five things I can do with just that alone."

As a player, I've never been interested in the warlock class, but as a DM, it's a giant knife that I get handed