In the cultivation world, humans and spirits could enter a special state of communion known as attunement.
However, the conditions required to achieve attunement were rather stringent.
First, the cultivator had to reach the Out-of-Body realm. Second, both human and spirit had to be willing, and they had to trust each other absolutely. If either side distrusted the other, attunement would fail. Furthermore, a contract had to bind the human and spirit together.
Of course, none of these was the most important condition. What mattered most was that the human and spirit attempting attunement shared a certain degree of spiritual resonance and compatible attributes.
The degree of spiritual resonance determined how long attunement could last, while compatible attributes prevented repulsion during the process.
For instance, if a cultivator with a fire spiritual root tried to attune with a water-attribute spirit, repulsion would arise within a few breaths. In mild cases, human and spirit would separate; in severe cases, they would suffer a backlash from the power of attunement.
A backlash from attunement was no small matter. During it, the different spiritual qi attributes of human and spirit would surge back and forth through their meridians.
Imagine water spiritual qi entering the meridians of a cultivator with a fire spiritual root. Ruptured meridians would probably be a mild consequence; in severe cases, even the qi sea might rupture.
Thus, although the Wind Spirit and Little Pearl were both formidable, Su Jiu had never considered attuning with either of them. After all, the Wind Spirit belonged to wind, while the Nine-Star World-Cleansing Pearl belonged to metal.
After attuning with a contracted spirit, a cultivator would also undergo certain changes. Their appearance and personality, for example, would take on some of the spirit's original traits.
Though called attunement, it was actually more like