Though the Spinner of Shadows is commonly associated with spiders, this simply reflects her wider role as an overlord of hidden schemes, of the careful vendetta and the joy of toying with a powerless foe. She has significant overlap with Sakinnirot, but the Spinner is less driven by burning hatred and more by hungry ambition; she is the schemer willing to climb a web formed of innocent corpses to achieve her desires
Though the Spinner isn’t one of the most powerful overlords, one of her strengths is her talent for remaining hidden—reflected by the fact that she had her domain in Xen’drik despite Sakinnirot’s claim on the continent. Because of this obsession with secrecy, it’s unlikely that the Spinner is involved with the Lords of Dust; her agents scheme alone, hiding even from their fiendish cousins.
Source: Chronicles of Eberron