Ikora believes that when you picked up Sagira's shell, you heard a fragment of a memory belonging to Savathûn. Your interaction with the Relic unlocked a new ability in you, one related to Darkness. She believes you can strengthen this ability at the Europan Pyramid, and in doing so, gain access to the full memory linked to Sagira's shell.

Complete "The Communion" mission at the Europan Pyramid.