A few weeks back I made the thread Can a Hexblade Steal a Weapon? in which a new player had touched Blackrazor and Wave during a long rest. He hadn't been trying to make them his pact blades, however, he had performed weapon bond on both of them. When it came out, we were naturally upset because in the RAW there doesn't seem to be anything at all we can do to stop this guy from stealing all our stuff and skipping off.

According to my DM, we are still attuned to our weapons, despite the hour-long ceremony, because the guy was not in contact with them the whole time. The fighter also says that if he wanted to, he could use "remove curse" to break our attunements anyway, despite the items not being cursed.

So, in a similar vein, can an eldritch knight bond with a weapon someone else is attuned to? Could a sentient weapon refuse the bond?

(As an aside, I had taken the first watch while the elf attuned to Wave, then he took the second watch because Wave is a trident of warning. I don't want to be that petty and say "If you wanted to screw with us, you should have opened your mouth at the table and said something in character instead of texting the DM the next session", but I didn't want to get one up rules lawyer-y either and here we are. Maybe once we leave this adventure, D&D will be fun again.)

RAW, there is nothing stopping an Eldritch Knight to bond with a weapon attuned to someone else. All it requires is:

• The item is a weapon
• The item is within reach the whole short rest
• The item is touched at the end of the short rest

So yes, Rules as Written an Eldritch Knight can bond with a weapon that is not his/hers, and this would not break attunement, since these two are not mutually exclusive. There is also nothing that indicates that sentient items can not be bonded with by an Eldritch Knight. If said sentient weapon likes being bonded is a different (and probably interesting story) altogether.

Edit: Also, your DM is right in stating that you are still attuned; they are different rituals and need to be performed seperately over two different short rests.

Edit 2: Also also, RAW Remove Curse does not work an a non-cursed item.

See, that's what I thought about Remove Curse. I even pulled the spell card and read the conditional, but he was insistent. I wasn't sure if there had been Sage Advice or errata that I'd missed. Thanks, RAJdeBoer.

It helps to read the book as a mathematical formula or even a programming language. Things that are not adressed do not change or are not affected. If you'd cast Remove Curse on an item conjured by the Minor Conjuration feature of the Wizards School of Conjuration, nothing happens; it is not a cursed item even if it is magical. I understand why the player would think it would break the attunement, but the "IF" is not fulfilled therefore it should not. Same that you could not use the spell on a piece of land that is cursed. It does not fit the "IF"

That aside; if such quarrels are happening in your game either talk to (or ask the DM to talk to) the player in question that you don't feel like is actions is helping the story forward and is not fun for you. You are all part of the same game and playing on the same team. Some party infighting can be fun and even dramatic moments can come from them, but if you feel like someone is trying to win the game and is doing so in such a fashion that it hinders your experience in the game, that's no good.

Hope you'll come to a solution that allows your group to have fun in the game.

If some npc would try to steal from me, I would kill them. If a player tries to steal from my in game, I will kill their character. When they whine, which they will, I will just say, you didn't care enough about me not enjoying the fact that you are trying to steal my stuff in character,  I won't care about you having to re-roll.

I would say that an Eldritch Knight can pull these shenanigans with Blackrazor but a Warlock could not. 

For the Eldritch Knight's Weapon Bond feature the weapon must be within reach for the entire ritual and be touched at the end. An Eldritch Knight can also bond with up to 2 weapons and has no restrictions regarding the type of weapon, i.e. this can be performed on mundane, magical, sentient and artifact weapons.

Compare this to the Hexblade, which I am assuming has taken Pact of the Blade at 3rd level. 

Hex Warrior grants proficiency with medium armour, shields and martial weapons and allows you to create a temporary bond with a weapon you touch to use Charisma for your attack rolls. This weapon cannot have the two-handed property unless it is also your pact weapon. Blackrazor is a greatsword and therefore has the two-handed property, meaning the Warlock must make it their pact weapon to benefit from Hex Warrior.

Looking at Pact of the Blade, the third paragraph states that the Warlock can spend a 1 hour ritual bonding to a magic weapon, turning it into their pact weapon. It also states:

The weapon ceases being your pact weapon if you die, if you perform the 1-hour ritual on a different weapon, or if you use a 1-hour ritual to break your bond to it.

So the Warlock can only have one pact weapon at a time, unlike the Eldritch Knight. 

Pact of the Blade also has the following stipulation:

You can’t affect an artifact or a sentient weapon in this way.

Jeremy and Mike have both clarified that this means that a Warlock cannot turn an artifact or sentient weapon into a Pact weapon: https://www.sageadvice.eu/2017/06/29/clarify-blade-pact-cant-make-sentient-weapon-a-pact-weapon/. So by the rules, the Warlock cannot use Pact of the Blade or Hex Warrior in conjunction with Blackrazor.

I will caveat this with your DM may rule differently and at your table your DM is the final arbiter of the rules. If this is a problem you should talk this through with your DM and clarify the situation and their interpretation.

Yeah, I don't understand how this occurred really. Neither a warlock nor an Eldrich Knight can link to a weapon just by touching it. Both of them need to stand next to or hold the weapon and "perform a ritual" for an hour. And I think it is barely necessary to point out that someone performing a ritual has a tendency to look like they are performing a ritual. They are saying the required chants, forming the required symbols, reciting the required formulae, sprinkling the required dust, invoking the required spirits and so on and so forth. Something that involves none of these things is not a ritual, it is just a person sitting there. If neither the player nor the DM informed you of this person performing a clearly weapon-related ritual at that time then I don't think that ritual actually occurred. No ritual, no link. If the DM wants to take these weapons from you then they can just do that using DM story magic, but a player doing it just by not mentioning the things they are doing is nonsense.

The very basic truth is that this scenario couldn't have happened the way this guy envisioned. Like I said, we split watch between myself and the elf attuned to Wave. If he had wanted in on watch, he should have said something out loud. Even if he had, however, Wave is with as aquatic elf who would have been aware of something going down during his trance, and my kobold is less than two feet long and curls up far away from anyone's reach to sleep (urchin background features).

We were just surprised that there were so few restrictions on this feature. I can't imagine this scenario comes up a lot, but from what we can tell, there doesn't seem to be an answer to this quandary anywhere online. RAW, this is a potential thing.

If this guy keeps this up, I have the game I DM to think about. Fortunately, this isn't our only option for D&D.

Odd scenario to start with, but the ultimate challenge with RAW is that it will never be 100% to prevent shenanigans.  A DM needs to use their head.

Personally, I would handle a bond with these rules: (and no this isn't supported by anything in RAW, but more of a spirit of things or RAI).  I also prefer a good story to a hard rule, so I have a bias.

First, that an intelligent weapon has to be consent for it to be bound.  Why would an intelligent weapon, who may not even want to be near the Eldritch Knight, let it be bound to that person?  Note that this case is by rule impossible for the warlock.  I could be persuaded to change that rule for the warlock (because, why not?  it seems to be an overlooked imbalance), but again, only if the weapon agrees, and perhaps there needs to be a quest to do this as it isn't something that can normally occur.  Breaking said bond voluntarily might also have a price in that case, including that the weapon wants to be used by someone else because of how insulting this isr, so this isn't a casual exchange.  It does make for an interesting story.

Second would be that I would rule that if the weapon requires attunement, then you must be attuned to it to even do the binding.  Otherwise you would end up with the weird case of a weapon, that you can't even fully use because of a lack of attunement, is useable as a focus and summoning, etc.  It doesn't make sense to me to not have the attunement as a requirement to bond.  I would rule a warlock would be in the same boat for consistency.  

Third, can an outside party break a bond?  My gut is sure it could be done with a wish, of course I could also just move that caster to a time when it wasn't bound (using the spell's own example of wishing someone dead).  Its an expensive action for a wish and it certainly isn't casual or common (I'd also say you had to be the weapons' presence just to avoid cases of having a huge impact with little personal risk.)  Could it be done with a dispel magic?  Maybe with a DC equal to 10 + warlock's level, with a spell slot at least twice the warlocks level.  But that seems too easy still for a villain or a player to abuse, so I might require a special one hour casting of dispel magic, with the weapon present to do this.  That isn't going to happen in a fight, but there could very well be sneaky story here to.  In short, I'd make it really difficult to pull off, keeping it from being casual.

The DM's word is final of course, and your mileage will vary.