Soulbond

The concept of the soulbond was heavily borrowed from the video game Drakan created by Surreal Software.

What is a sould bond?
The sould bond was a ritual created by an ancient organization called The Order of the Flame. Soul bonding within the Order was primarily between one man and one dragon. The ritual required a lacrima for the dragon, a seith mage and an incantation by the pair to be bonded.

The lacrima would be infused with the dragon's magic as well as the intended's. Once both magics were present the Seith mage would activate the lacrima turning it into the dragon's soul crystal causing the souls of those participating in the ritual to be joined together, becoming one soul.

There are some side effects to the bond. When the human dies the dragon they are bonded to dies as well. If the dragon dies, the bonded will live out the rest of their life as a half of a being. Once dead, however, the human's soul is forced to wander as a soul shadow until someone brings their dragon's soul crystal and places it onto their remains, at which point their soul will be released to the afterlife.

The only exception to these effects seems to be if the two that are bonded die of old age. When this happens the human and dragon both die at the exact same time and both their souls are released to the afterlife.

Bonded pairs can sense each other no matter where they are and they are capable of feeling each other's emotions.

The soul bonding rituals were lost to time when the Order of the Flame was destroyed, and are not known to be in practice currently. Their writings made their way to Fairy Tail's Magic Library where they were found by Levy.

Although the bond is thought to be irreversible this is not accurate. The bond can be broken by the dragon but they have to forfeit all connections to their matching soul for eternity. Excerpts of this page were taken from Soul Bonding