Thread:TheSecondEdgeOfTheBlade/@comment-28928032-20161203064336/@comment-28928032-20161217200259

To adress your other arguments

In the game a pistol can be obtained, yeh it may not be a full blown sniper rifle, but the game also notes the pistol is antique, meaning it is old, and considering all the modern equipment we see at the end of the true pacifist run, we can assume a sniper rifle was probably developed

His backstory is quite similar to Sans and Papyrus's, who are described by the shop keeper as "just appearing one day"