Evelyn's Bargain

This spell forms a bond between any number of willing creatures within range, binding them to an agreement.

By targeting a vellum contract, you magically enforce its conditions. Any willing creature that signs the contract using at least some of its blood during the spell's casting is bound by its conditions and connected to any other creature that signed it, as long as they are aware of the repercussions of breaking the contract.

A creature that signs the contract unknowingly of its repercussions is exempted from it, gaining none of its benefits and suffering none of its downsides. The details of the contract can be as elaborate as you wish and can include any number of exceptions or the like.

After one hour, the contract gains magical protection, with an Armor Class equal to your spell save DC, hit points equal to 5 times your caster level, and resistance to all damage. Any creature bound by it can use an action to conjure a magical copy of the contract, but if the original is destroyed, so is the contract. Dispel Magic only ends the contract if it is cast at a level higher than or equal to the spell, and only if it directly targets the original contract.

A creature that breaks the contract's conditions suffers an effect detailed in the contract, although death or worse cannot be a consequence unless the spell is cast at 4th level or higher. The consequence must be something within the realm of the creature's abilities; for example, you could cause a target to fall ill, but you couldn't cause it to summon matter from nothing unless the creature had that ability. 

Additionally, unless otherwise specified in the contract, all creatures who signed it are instantly aware if one of them breaks it.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the consequences of breaking the contract can involve death. If cast at 7th level or higher, consequences may involve the soul, such as binding it. Casting the spell at 9th level allows the contract to manipulate the signatories' minds, preventing them from violating its terms. Even deities cannot break such a contract, though precise wording is crucial; whom it binds is of utmost importance.