The Familiar

You are an ancient and powerful spirit. Today, the boundary between worlds is thinning, and you, stretched out on a gigantic branch of the World Tree, watch the birth of hundreds of multicolored lights. These are the voices of people calling upon their familiars.
Some are pale and barely glowing—enough to suffice only for a weak, lesser spirit. Others glow brightly and purely, like tiny stars. A host of spirits scurry among the branches: they fly toward the glow they find most appealing and disappear into it with a brief flash of light.
But your attention is drawn to four voices that stand out from the rest of the choir. The first blazes a rich, dense violet—it conveys a thirst for power and vengeance. The second is blindingly bright, almost white, but this whiteness conceals not emptiness but a frantic concentration of pure will. The third pulses scarlet. It evokes the silence of the night and the ringing of drops of blood dripping from the tip of a dagger. The fourth shimmers emerald, smoothly fading to a deep, impenetrable black—it conveys wisdom bordering on bottomless determination and obsession.
What choice will you make?

(You can describe what kind of spirit you are. By default, you are the spirit of an ancient dragon in human form.)