Destroy 30 Undead Ravagers, then return to Brother Anton at Nijel's Point.
I will be frank. We are at war with the Scourge. It is an evil that corrupts our people and infects our land. It must be stopped before it overwhelms us and drags our world into shadow. We of the Scarlet Crusade have sworn to fight the Scourge with body and soul.
If you are with us, then gather your courage and prove your allegiance--destroy the undead ravagers of Desolace, in the Valley of Bones to the south.
Do this, and the Crusade will embrace you.