Twin Moons [2]
It was almost like teleportation.
When Damien pulled the trigger, it all happened in an instant, far too fast for such an intensive process.
The trigger being pulled was a catalyst. The black gems in Damien's wrists lit up, sucking in Damien's mana like a vortex. This mana was then circulated through the gem itself, being compressed and concentrated multiple times over.
Only when this process ended would the mana enter the gun. As for the process, even Damien couldn't quite understand how the mana went from the gems to the guns. The only thing he could sense was that there was some sort of connection between the four objects similar to Damien's Celestial Mana Threads.
Regardless, the "bullet" was transported into the gun's chamber and propelled forth using mana conceptually mirroring a ray gun.