User blog comment:Le Rottweiler/Why does Ranger have an ax?/@comment-1496755-20150416153653

I believe Ranger's axe is a remnant from the time when Quake (actually Timequake) was supposed to be a pure fantasy game. Perhaps there would have been axe-wielding monsters.

In the game's present state, the axe is a complete mystery - it is the only one of its kind in the entire game. We can assume Ranger got it from his home base before/while the first invasion began. Or picked it up from a fallen enemy, as you suggested (this would mean this enemy was one of a kind too).

It's little mysteries like this that make Quake even more fun to experience :)