Though technically not the "base" version of the Dark Souls board game, Tomb of Giants is a standalone core set that doesn't require the original Dark Souls board game, which isn't on sale, to play. Tomb of Giants takes players to the catacombs to wage war against Gravelord Nito, a truly monstrous skeleton of a being who fittingly has an army of skeletons.
Here's what you get with this dungeon crawler tabletop experience: