This quest is apparently immediately broken. Upon taking the quest and going to the first objective, a tower that needs defending, the NPC spawns in order to say 'go away bloodfiends' and then....Silence. No bloodfiends spawn, no mobs spawn, and the player cannot progress. Restarting the client, Unlogging and relogging, and abandoning and re-accepting the quest does absolutely nothing.
This is an issue on NA-PC.