I cannot find where to buy season of the haunted pass, which is required for some quests
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The only way to get the Season Passes that have rotated out is through upgrading or purchasing the Deluxe Edition of the current DLC. If you already own Witch Queen, you should be able to purchase the Deluxe Upgrade for it on your platform store or through following the links in game that take you to order it on your platform store. If you do not already own Witch Queen, then you'll need to purchase the Witch Queen Deluxe to get any past Season Passes.