The massive blackrock constructs created by the Guardian contained miniature "echoes" of their geometric form within them, and these objects could be used to achieve a variety of magical effects if removed. In Ultima VII such prisms existed within the (Sphere, Tetrahedron and Cube Generators, which had been erected to assist in the red titan's invasion of Britannia. In the course of forestalling such an eventuality, the Avatar would have to obtain the prism from within each Generator's defenses in order to destroy them. One of these objects, a miniature blackrock cube, had the curious effect of coercing whomever stood in its presence to speak truthfully, which allowed the hero to glean much needed information about Fellowship operations. Eventually, all three prisms would have to be fitted into the pedestals of the Black Gate in order to pierce the barrier that surrounded it.
Later, in the course of Ultima Underworld II, the Guardian would craft a massive Blackrock Dome over Castle Britannia, trapping all who had been feasting within. In journeying to dismantle this prison, the Avatar would discover a prismatic "echo" of the casting in bottom of the castle's sewer system, in the form of a Blackrock Jewel. Through this gem, the Avatar visited eight different worlds, retrieving an additional reverberant prism from each one. These eight gems (shaped like a small sphere, cube, diamond, large sphere, cylinder, tetrahedron, rectangular cuboid and heart, respectively) would be treated by the court magician, Nystul, before being reabsorbed by the larger jewel—a process that would slowly weaken the structure of the surrounding dome.
|“|| After that task has been completed, a smaller Tetrahedron will remain in place of the larger one. The Avatar will have great use for the smaller generator, and should take it.|
By solving the puzzle of the red and blue Moongates, the Avatar can obtain the smaller Sphere within. This, too, is an important key to solving the Avatar's quest, and should be kept like the small Tetrahedron.
And once inside the generator, the Avatar must solve a puzzle, avoiding the dangerous fire traps designed to prevent access to the smaller Cube. After the small Cube is obtained, I will again speak, telling the Avatar to carry it to Buccaneer's Den.