Fain doesn't need an ter'angreal for that, and as far as we can tell, he's east moving on SG, not in Saldea.

He's been controlling Shadowspawn since TGH. He succeeded well with Trollocs even then, but had problems getting obeyed by the Myrddraal that soon escaped control and tried to countermand Fain's orders (that's why the group was turning east for a while when the Myrddraal reasserted control over the Trollocs and DFs, before Fain got control back, killed a bunch of people as an example, and had everyone move south again. He ended up torturing and killing the Myrddraal, the changes of directions stopped.

But by TSR Fain managed to get obeyed by a Fade too.

Fain's powers/control have been steadily on the increase since his merge with Mordeth.