Looking to develop the following magic item type for a major place in an upcoming campaign. It's a complicated one, which will need thoughtful vetting. I am hoping people will abuse it creatively and entertainingly.

Arcane Contracts

wonder, varies, requires attunement

Sometimes one wants to enforce a contract through magical means, or provide their end of a contract through magical means (or both). This is an arcane contract.

A common misconception exists that the paper and ink which describes an arcane contract is a magic item itself. In truth, the contract’s physical representation is just a means of helping people understand the contract and reference its terms. One need not possess the paper of a contract to swear to it, and destroying the paper does not end the contract. The magical item has no physical location, and this creates some interesting situations. Detect Magic will register the item on someone attuned to it or while someone is reading the terms of the contract aloud, but not in any other case. Attunement can be done, as an action, by anyone provided they know the terms of the contract, intend to agree to it at that moment, and so long as there is at least one available signator (see below). As they have to know the terms of the contract, anyone deceived as to the contents of the contract cannot agree (attune) to it. Similarly, magic cannot compel any individual to attune to an arcane contract. Once the contract has been agreed/attuned to, the subject’s name appears on a signator’s line on any physical representation of the contract.

The terms of the contract can vary considerably, but all contracts have the following aspects, called clauses;

• 2 or more signatories’ spaces
• 1 or more responsibilities
• a spell cast as part of a responsibility (above), is given the duration of the contract
• concentration
• sanctions (optional)
• duration

Signatories are those signing the contract. Signing the contract, for the purposes of this item, is the same as attuning to it. Each individual signator is a separate clause for purposes of the number of clauses the contract can apply to. This is an unusual example of an item being attunable to more than one person at a time. Note that a signator is someone beholden to the responsibilities of the contract, not just anyone named in the contract. Thus, if the contract includes the phrase “until the warlord Grimcok is slain”, that doesn’t make Grimcok a signator.

Responsibilities are those things the signatories are expected to do or not do. Each individual task or prohibition, for each individual signatory, is an individual clause. That means responsibilities which apply to multiple signatories are multiple clauses. For example, if there are three signatories and the contract states “All must defend the caravan from threats”, this is three clauses, not one.

Responsibilities must specify who they apply to. If the wording of an arcane contract requires an act or prohibition be taken and it is unclear who that applies to, all signatories are de-attuned to the magic item.

If a signatory is a spell caster, and a responsibility states that they must cast a certain spell, they may cast it when attuning to the item or at a later time. Failure to cast the spell by the end of the contract’s duration, or by another time listed in the contract’s wording, breaks the contract and activates its sanction, if any. The contract can also ‘hold’ the spell, if the wording dictates a trigger, causing it to activate as if it were cast at the moment it is triggered. This is often the purpose of the contract. Any components of the spell must be supplied during the attunement. 

Spells with a concentration requirement held this way can have that requirement negated, though this constitutes an additional clause of the spell. Circumventing concentration limits is another typical purpose for the contract. The spellcaster is free to reclaim that spell slot while the contract is attuned, in whatever manner they usually do.

Spells with a non-instant duration and which have only one target can be upgraded to have the same duration as the contract. This is treated as an additional clause per spell.

Sanctions are what happens if someone breaks the contract. These can include any of the following, and each is an additional clause, and can include the same sanction multiple times;

• The loss of any number of hit points, including conditionals like ‘all’, ‘half’ or ‘As many as Dorin lost because of Pollit’s incompetence.’
• Advantage or Disadvantage on a roll. This can be defined further, such as ‘Disadvantage on your next save against a spell’. 
• Gain a level of exhaustion. 
• One of the signatories can cast a spell that they specify as a sanction. Breaking the contract makes the individual breaking it subject to the spell as if it were just cast, from touch range, with any applicable saves failed or attacks counting as automatically hitting. Multiple sanction spells can be applied this way as part of the attunement, and each is an additional clause per spell and per signatory.

While a sanction is typically a punishment for breaking the contract, creative use can make it into a benefit and/or the point of the contract. An arcane contract might have the signator swear ‘I shall not allow myself to be harmed in a fight’ and levy a sanction of Cure Light Wounds. 

Duration is how long the contract holds for. When the duration of a contract expires all signatories are de-attuned to the magic item, and the same or different signatories can be applied.

Contracts of greater rarity can hold a greater number of clauses and can hold for longer durations. 

For purposes of magic item creation, if the terms of the contract can only be fulfilled once (see the Grimcok example above) then the arcane contract is considered a single-use item.  

Hell yeah this is exactly the kind of thing I was just looking for ♥