We study the Ramond twisted representations of the affine W algebra W(ḡ, f) in the case that f admits a good even grading. We establish the vanishing and the almost irreducibility of the corresponding BRST cohomology. This confirms some of the recent conjectures of Kac and Wakimoto [KW5]. In type A, our results give the characters of all irreducible ordinary Ramond twisted representations of W(...