My 3rd riddle, so hopefully this one isn't quick to figure out like the rest. But I'm sure it's easy enough for some of those experts in the group. [i]My kind are swift, quick, and eager to cut. Precise with what we do. You may see me, then you don't, just depends on the job. We were excluded from the king of time. Then needed to kill the bone walker God. We've brought disaster to the crucible with lingering pain, and the last say.[/i] Who/what am I?