Spiritual Communion is one of the oldest Legendary Abilities, dating back to the Primarch Nergal. While Necromancy usually taps into the Souls of others to power oneself and shamanism creates an equal relationship, the user of Spirit Communion uses his own soul to bolster allies. The idea behind Spiritual Communion is to give powers to others and fully trusting in their ability to grow. Some say, it only reveals the true potential strength of the target. Furthermore, by creating this link, the soul of the user becomes more and more permeable, resilient and powerful in the long run (at the opposite of Necromancy which degrades the soul).

Spiritual Communion also allows the transfer of knowledge and memories between users but cannot be forced unto others. It is a benevolent form of magic, that requires a selfless state of mind. The bonds that it creates are powerful and form little to no Fatebinding. However, its usage was lost when the primarchs left the World.