A Heaven-grade weapon was forged out of the mind and soul.
Even though there were ways in the outside world that could create such a weapon, the essence of it was still the mind and soul. Like a person's arms and legs, a Heaven-grade weapon had a connection to its owner.
If the owner died, their mind and soul would wither away, and the Heaven-grade weapon would also naturally dissipate.
It was similar to when a person lost his life and his flesh would also perish.
However, there were some differences between the metal chain and the golden spear.
These two Heaven-grade weapons were brought back to Earth when their owners were still alive, severing the connection between them.
Since the owners hadn't died at that point, the weapon didn't perish either.
The conclusion of this was that these two weapons were still around.
