Good call. I actually have both the evil costume and Sestieh. Just looked and I think you may have been smart to ask. I’ve not built either yet, but I don’t think the will be compatible. The evil set is literally just the bangs for the front part, where as Sestieh had a much larger one that sweeps back. I think the sides that curve back will interfere with the hair that gets attached to the head with the evil costume.