Todd the Gray is a Sluagh assassin.
There are spies and there are assassins, and then there is Todd the Gray. When the sidhe sought to instill terror on the Night of Iron Knives, Todd was the commoners' response. Personally responsible for the deaths of at least two dozen nobles, The Gray (as he is called) hasn't been heard from in well over a decade. Perhaps this is because of the huge price put on his head by nobles in practically every kingdom in Concordia; or maybe it's because he hasn't found a target worthy of his skills recently.
When last seen, Todd dressed (unsurprisingly) entirely in gray. His favored weapon was a wickedly curved chimerical dagger supposedly named Gwynyfara after a lover of his slain in that infamous night. The morning before the coronation of High King David, Todd left Gwynyfara in the breast of his last victim, Lord Gwystyl ap Eiluned, the sidhe commonly credited with being the author of the Beltaine Massacre.
The longer Todd stays in retirement, the more his legend grows. At this point, there is a whole cottage industry grown up around Todd stories as crawlers compete in describing The Gray's exploits on one expedition or another. A well-told Todd story will win a young sluagh a great deal of respect in the eyes of their elders.