I’m not providing inventory example in demo project for plugin. And plugin is purely about Quest System (not about dialogs, inventory, skills or other RPG elements, because it’s not only for RPG).
But of course, if you have an inventory system, you can make any kind of checks for it in requirements blueprints(for quests and quest tasks).
For example you can check if item is exist in inventory and if it’s not, the player can’t complete a quest or task.
Because requirement checks is universal thing(you have an implementable function with boolean as a return type), you can check everything what you want.