How can I prevent the rogue from placing items in my character's backpack?

Question

We've a rogue in the party with proficiency and magic items assisting their Sleight of Hand. With a +12 and always having advantage, they roll, on average, a 25. They have gotten to enjoy stealing items and then placing them on my character. I'm not the GM, I'm a wizard.

Last time they shoved an item into my backpack which, for the sake of this question, my character was wearing on her back. With a roll of 28 the GM didn't even ask me to roll perception because at a nat20 I would've gotten a 23.

Although I hate the ruling I will go with whatever is decided, so I'd like to know -- in game, what can my character do to prevent this in the future? If the GM rules that high enough roll for Sleight of Hand will get into anything, how can I get creative in preventing this?

Answer 1

Tell them to stop

If it’s bothering you as a player, that should be enough. PvP is only fun if it’s fun for everyone.

If it’s bothering you as a character, then the rogue may or may not stop. If they do, great. If they don’t, then a calibrated escalation is needed - “Ha, ha, that was hilarious. You know what else would be hilarious? A Suggestion that you repent your ways and turn yourself in to the authorities. We’d all LOAO at that, wouldn’t we?.”

Answer 2

This doesn't really seem like a problem to be solved in-game.

You're not having fun, and the ultimate cause is another player choosing to have fun at your (not just your character's) expense. You need to talk to the rogue's player about this. If they're experiencing My Guy syndrome, basically all the ways to handle it are out-of-character. Trying to fix it by in-character means just adds to the challenge, and it doesn't stop what you clearly dislike.

If you really want to solve this in-character

All that said, if you must solve this in character (because you want to; don't let them pressure you into accepting being bullied at the table), see if the DM will allow a slightly altered version of Alarm that can work on any "closable" thing (extending from just doors, windows and specific areas); it's not a major change to the spell after all, backpack flaps and certain forms of pockets are not morally distinct from doors or windows, just smaller scale (the top two comments on D&D Beyond are someone asking if it works on backpacks and someone else saying "Yes"; it's not strictly RAW, but it's very close). Then cast it on all the possessions you need guarded with a trigger of being touched. Doesn't matter how stealthy they are, the moment they touch your backpack/robe/whatever, you get an immediate mental ping to check things. It's a Ritual spell too, so at the cost of 11 minutes per item warded, three times/day, you can keep everything well-protected. You'd be nuts to continue playing this game if it's upsetting you, but if it's what you like, have fun.

Answer 3

Let's assume you want to mess with the rogue, not do something boring like talking to him. And since you're playing a wizard I'll focus on spells.

Alarm (audible): As mentioned by ShadowRanger, put an alarm on your backpack. Alarm has casting range of 30ft. So if you want to escalate, you can also cast it on your rogue's mark when he's trying to steal something.

Disguise self: Make yourself look like there is no backpack. Let the rogue figure it out. Or, alternatively, swap the backpack for a bag of holding and disguise self to look like you still have a backpack:)

Secret chest: Replace the backpack with a chest accessible only by you.

Bestow curse: Curse your rogue so he doesn't have a crazy Sleight of Hand score anymore. Or create a designer curse that would make the rogue cluck like a chicken for a full minute whenever he uses sleight of hand :)

Antilife shell: magical restraining order. A bit boring for my taste, but gets the job done.

Geas: Command the rogue to stop touching your stuff or get slapped for 5d10 if he tries.

True Polymorph: Convert your backpack into a backpack mimic. Make him bite everyone but you. Problem solved :)

Answer 4

Fight fire with fire

You are a wizard. You should know better than to use a backpack, which will ruin your precious books anyway. No, a proper wizard uses a lightweight travel crate from wood with a lock on it. Why? Oh, you don't see it?

• Arcane Lock - The travel crate is enhanced with arcane lock, putting the sleight of hand of the thief to some difficulties as he now also has to bypass the lock. Sadly, this might be nothing more than a stopgap.
• Add a simple music box into the chest's lid, that is to be wound from within and start to play if you open the lid. This will not stop the thief from trying to sneak something in, but it will make it much harder for him to succeed.
• Glyph of Warding - While you are not moving, you secure your luggage with a glyph of Warding. Sadly it doesn't help to secure the luggage underway.

Oooor... of course, you go the full length and skip on carrying your luggage forever. Ask the DM what a medium-sized chest from Pearwood costs. Buy it, cast (or pay someone to cast) True Polymorph on it and treat the resulting Luggage fairly. Have it follow you all days, and order it to never open up to the thief.

Answer 5

Magic Mouth

Just put a Magic Mouth on the inside of your backpack's flap that goes off whenever anyone or anything other than you opens it or intrudes inside the backpack.

For added fun, have it shout "THIEF! THEIF! THIEF!", and then you can Magic Missile them for "trying to steal from you".

Lying

People underestimate the power of lying:

• Q: Why do you have this stolen item Wizard?
• A: TurdBreath the Thief gave it to me.
• Q: Why should we believe you and not them?
• A: Well one of us is an actual thief, it's their fricking profession. So who do you think would and could steal it?

More Magic Mouth

Magic Mouth really is a crazy spell for pranking:

• Put it on their saddle to let out a huge ripping fart-like sound when the sit on it.
• Put it on one of their boots to trigger a couple of seconds after they try sneaking/backstabbing to yell out "WARNING! A THIEF IS TRYING TO SNEAK UP ON YOU!"
• Put it on their thieves tools to let out intermittent loud clicking and scraping sounds when they try to pick a lock.

Answer 6

Aside from what you want (solving this in-game), and what others rightly tells you to do (solve it outside of the game), there's also a middle ground:

Ask your DM for magic item countermeasures and disadvantage for the rogue

Your DM was the one who gave rogue magic items that contributes to the bonus that seems to exceed bounded accuracy of 5e. It's only fair to expect and demand fair play from DM.

Your DM is the one that always grants the rogue advantage. But now your character suspects that rogue all the time. So rogue should get a disadvantage when acting against you, one that would nullify the advantage. And unless specific class feature says so, "always advantage" seems broken and for the sake of fair play should stop. Advantage is something that needs to be earned.

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For the purely in game solution, you could start randomly zapping rogue with a cantrip that targets his weak save, "sorry, I thought you were reaching for my backpack again" and see how he likes. If your DM is any fair, rogue should never make the save. If that's your kind of fun, go for it! I'd rather solve it outside of the game, but that's just me.

Answer 7

As others have said, "please stop" is an appropriate response. However - consider whether "Go ahead and continue, but make it stuff that's harmless, not incriminating / dangerous / gross," would also work for you. If there's a way that you can modify the situation so that the pranks don't bother you but the rogue still gets to have fun pranking, that's a win. Hiding stuff where someone else will be surprised to find it can be a harmless game, if the stuff is harmless from the perspective of the recipient. And wizards have a huge tool set for both trickery and trickery-prevention if they want to play the game right back.

Your DM might not be into playing the kind of game where NPCs aggressively go after the party rather than politely waiting in dungeons until the party kicks down the door. But it's worth considering that if your friend can put the stolen candlesticks into your pack, a sneaky NPC of appropriate challenge rating who approaches the party feigning friendship can poison your food, steal your gold, or soak your spellbook in ink.