D stands for dice. It's like in DnD if you played. To check if attack was successful you throw dice 20 and if attack successful you throw your damage dices, in case of great sword it's 2 dices. Kinda forget that not that much played DnD. Otherwise thanks!
Actually amazed how much have you done, amazing idea and even better execution. Hadn't checked Multiplayer but option itself is impressive. Congratulations! :D
