Reciprocal Rune

An acient Relic that summons one of oryx's lieturnents in the court of oryx.

Reward recieved from completing quest Shattered Past.

Shattered Past -

1. Collect your first Calcified Fragment

2. Talk To Eris Morn

3. Collect 5 Calcified Fragments

4. Return to Eris Morn and Recieve your reward Reciprocal Rune

Source -http://www.gamersheroes.com/game-guides/destiny-the-taken-king-guide-shattered-past-guide-find-all-calcified-fragments/