 Why are the webfoots chasing Stinson and Sybtl?
He touched the pencil-line scar behind his ear where the cylinder was buried, marveling at the power stored there, power to fling him from earth to this fourth planet of the Centaurian system in an instant. A gray, funnel-shaped cloud of dust stood off to his left. These are the undesirables, the incorrigibles, the nonconformists from the sixth planet. And this is contrary to the greatest law of all—that an entity, once in existence, can never cease to exist." "As for the webfoots," the wind devil, or Sand God, said, "I will destroy them. They exist, therefore they always will.
 The webfoots think Sybtl did not please the God.
 The webfoots think Stinson took Syblt against her will.  Stinson accidentally killed one of the webfoots while disarming him.  Stinson murdered the leader of the webfoots.  The webfoots think Sybtl did not please the God.