A small ring given to a select few amongst those with multiple souls within the same body.
The ring has two gems, each with the corresponding alignment color of the souls. Green for good, grey for neutral, red for evil, with a blend of blue for lawful and yellow for chaotic.
The ring acts as a small dial. The wearer will be able to turn the dial to give control to the corresponding soul at any time. Unfortunately, the body remains the same, so any abilities held by the extra soul will behave within the limits of the true soul.