Ty'salaera's Vow

When you cast this spell, you enter a magically binding contract with another willing creature that you can touch. Both you and the creature utter a simple vow, no more than 15 words in length, as part of its casting. Example: “I vow to not harm you or your party.” You or the creature, with permission from the other, may choose to abstain from this action, creating a magically binding contract for only one creature. Once the vow(s) is/are uttered, identical marks appear upon the participant’s skin in any place they choose.

While appearing mundane to the naked eye, the mark will register as magical by a detect magic spell. An identify spell cast on the mark reveals the exact nature of that creature’s vow, if they made one during the casting of the spell. At any point during the duration of the spell, either creature may initiate the process to nullify the vow by touching the mark and speaking a command word of their choosing, decided during the casting of the spell. Once both creatures do this, they are released from their vows and the spell ends causing the marks to vanish. If the spell is dispelled or either creature dies, the spell ends with no indication of the cause and the marks disappear. The caster may only have a number of Vow spells active equal to their proficiency bonus.

During the duration of the spell should either vow be broken (gray areas up to GMs discretion), the other creature knows that the vow has been broken and gains the following benefits against the creature that reneged for 24 hours, after which the spell ends:

• You know the general direction and distance (increments of 5 miles/km) of the creature that broke their vow. You have advantage on any Wisdom (Perception) or Wisdom (Survival) check you make to find them.
• Whenever you make an attack roll against them or a saving throw against a spell cast or effect caused by them, roll a d4 and add the number rolled to the attack roll or saving throw.
• Whenever they make an attack roll against you or a saving throw against a spell cast or effect caused by you, they roll a d4 and subtract the number rolled to the attack roll or saving throw.

When you cast this spell using a spell slot of a higher level, the duration of the effects doubles for each level past 2nd.