Well, Giovanni definitely killed those two Magmar in the original arc, though Koga's Arbok is capable of regenerating itself if it loses part of its body.
The Magmars got offed in Volume 2, and the Arbok incident happened in the last chapter of Volume 1.
I know. Volume 2 was my first volume (I now own Volumes 1-3 and 5) and when I first read the Magmar thing, I was shocked. Also, there are Pokemon zombies in chapter 13 of Volume 1.
Wait a minute..... I thought we went through this. The whole thing with the magmar and all that.