Besides Thorns - and the Heart's Thorn - Shadows have other, harsher powers that they can bring to bear against the Wraiths they're shackled to.

Unlike Thorns, there is no benefit to be had to the Wraith from these abilities. These dark tools are for the Shadows' use only, and bring only pain, ruin and decay to Wraiths. Smart Shadows use them very carefully and sparingly, given their tendency to backfire, but the right gamble at the right time often pays off in harsh dividends.