Memory Stone, the marvelous invention of Da Ming.
Zhou Li had always felt that the Da Ming of this world was very out of the ordinary; apart from the damn inability to die, the most prominent feature was the variety of bizarre inventions.
For instance, the feudal society's road system and Gaoma Station that greatly shocked Zhou Li, the division of powers into a tripartite system where the Prime Minister's Cabinet shouted "your dad is the King," and of course, the Memory Stone, which Zhou Li considered to be comparable to the fifth great invention.
The Memory Stone, which looks like a rock but is actually a specially processed metal cube, has a unique mineral panel inside that can record the sound, light, and images in front of the user. It seems unremarkable, yet it possesses an amazing feature.
The development level of this thing is linked to the user's Spirit Qi or Immortal Qi.