From the post:
Witchling Handlers are an advanced pursuit in the upcoming Through the Breach supplement, Above the Law. As one might expect, Witchling Handlers can order Witchling Stalker subordinate characters into combat, providing a very effective (and very volatile) fighting force. When a character becomes a Witchling Handler, she also gains a runed weapon that not only ignores the Incorporeal rule but also allows her to command all of her Witchling Stalkers with a single action. Furthermore, a bit of concentration while holding the runed weapon allows the Handler to discern the direction and distance to every Witchling Stalker under her control, which will no doubt open up some interesting "hide a Witchling in a crate" plans on the tabletop.