Defend the Ash Legions Camp
That event can be a tough one to beat. It’s best to have a few characters sitting right on top of the ghost spawn points so they can grab aggro immediately so the ghosts don’t use AoE on the tents.
It’s also worthwhile noting that I believe this event does not trigger until somebody finishes the “blow up statues in the Decimus Stones” event, so if you want to keep the waypoint permanently uncontested, don’t start that event.