Instructions
Take the Haunted House portal to Crimsonwood Keep. Climb up the first available rope to the next portal. Once you are through the portal, walk to the right until you reach the final portal. This will take you to a high platform full of Windraiders.
Search Crimsonwood Mountain for Windraider spawn points. Windraiders have been found in Upper Ascent, Lower Ascent, the Cavern of Pain, the Cavern of Valor, the Cavern of Shame, the Cavern of Honor, and the Cavern of Fortitude.
Travel to the Phantom Road to seek out more Windraiders. Windraiders can be found by the road itself, but they can also be found near all three crossroads within the Phantom Forest.