Ride south into New Avalon to the Scarlet Tavern at (56,79). Turn in Behind Scarlet Lines and pick up The Path Of The Righteous Crusader and Brothers in Death. Head out and ride to the Scarlet Hold at (62,68), fight your way inside and go upstairs (once up the first set of stairs, take the left door and go right and right again). Take the [New Avalon Patrol Schedule] from the table.

Now head back downstairs into the basement (take the first left once you get downstairs) where you will find Koltira Deathweaver. Turn in Brothers in Death and take Bloody Breakout.

Koltira Deathweaver will now cast an Anti-Magic Zone in the room and waves of soldiers will come down to fight. Stay inside the Anti-Magic Zone and you will take almost no damage. Eventually High Inquisitor Valroth will arrive, use Plague Strike to counter his Renew and run back into the Anti-Magic Zone if you are knocked out. You should be able to solo him with ease if you do this. Loot [Valroth's Head] from his remains on the ground.

Pick up Ambush At The Overlook, head back outside and go east to the Scarlet Overlook at (60,77). Use the [Makeshift Cover] provided to make the Scarlet Courier appear. Kill him and loot [Scarlet Courier's Belongings] and [Scarlet Courier's Message] and return back to the Tavern at (56,79). Turn in the quest and take A Meeting With Fate.

Ride to King's Harbor at (65,83) and turn in the quest and take The Scarlet Onslaught Emerges. Ride back to the Tavern at (56,79) to turn it in and pick up Scarlet Armies Approach... Take the portal that opens back to Acherus (or speak with Orbaz Bloodbane to reopen it). Back in Acherus, turn the quest in at the center and take The Scarlet Apocalypse.