Rings of Kynaios and Tiro

Ring, artifact (requires attunement by a pair of creatures friendly toward each other)

Price: 600,000-900,000 gp | medium sentimentality

This pair of rings belonged to Kynaios and Tiro, legendary joint kings of Meletis who overthrew a tyrannical archon and founded the polis over the ruins of his empire. They were lovers who ushered in an age of enlightenment and peace, though their tale became lost to time. Two creatures friendly to each other must attune to the rings at the same time. You can neither attune to both rings nor a single ring by itself. While wearing the rings, you can communicate via telepathy with the other ring’s owner no matter the distance between you, even if you are on different planes.

Paid

When you’re within 10 feet of the other ring’s owner, both your ability modifiers become the sum of your individual ability modifiers. In combat, when you’re within 10 feet of the other ring’s owner, you each gain an additional action and both of you can use an action to allow the other to take an action instead.

Overpaid

If the other ring’s owner is 30 feet or closer to you and is the target of an attack that would hit them, you can use your reaction to move beside them and be the target of the attack instead. This reaction doesn’t provoke opportunity attacks.

Destroying the Rings

The rings are immune to all damage unless the souls of Kynaios and Tiro revoke their blessings on the rings, in which case they lose all magical properties.

Source: The Gray Merchant of Asphodel