Can you explain the different approach Grimmgard takes to the Wild Die from "standard" D6?
D6 2nd Edition employs a "Wild Die" as a 6-sided die thrown in additional to your skill rolls to take an action. Instead, GD6 (Grimmgard D6) employs the additional 6-sided die as a "Luck Die." The result of this extra die is ignored unless it comes up as a 1 or a 6. A 1 result reduces your Luck pool by a point, while a 6 result adds a point.
Feel free to use your own House Rules and change it as suits your preferences! Some players have commenting that a D6 Luck Die made changes to their Luck pool too frequently, so they used a D10 or D12 instead. Others opted not to use the Luck Die during combat in order to keep play moving quickly.