Brock is an explorer who found Shangri-La along with Gary, who works for him. He was trying to prove the existence of Agartha.
The players must help Brock and Gary escape Shangri-La. Over the course of the escape, Brock recognizes that the temple wasn't made by an ancient civilization, but was built by people of modern-era, while Gary tries to convince Brock to leave the place. After finding the altar holding the Focusing Stone, Brock attempted to remove it, only to be teleported along with Gary back to the very beginning when they found the temple. Thus, they are put in an infinite time loop.
However, if the players decide to not help them, Brock will leave a final recording after being trapped in the temple's structure, indicating that Gary died from unknown reasons and that he and his radio will "soon follow".
In Zetsubou No Shima, a cipher reveals that after the original timeline was reformed, he and Gary were killed during a weird atmospheric event whilst on a private plane.