Victor Vran

In the first real map: "The Royal Gardens"
Press to open up the map, due North you'll see your first checkpoint, a green star like circle, this is located on a bridge, now when you get across the bridge, head West (aka Left) & in the corner (furthest South West, North of the bridge) you'll see a big pile of red dots on your minimap these are of course enemies but not just any enemies, no they're Spider Eggs which are also needed for a challenge: "Slay 25 Spider Eggs" so equip your Hammer & get to the eggs as fast as possible before they hatch (as far as I could figure, they only start hatching when you're within visual range or at least so close that they are about to enter your view) & as soon as you get there press to launch in to the air & smash down on the eggs, I destroyed all but a few & popped the cheevo as well as the challenge.
The Hammer I used was a so-called "Vicious Hammer" with 45% Critical Damage Increase doubt that made a difference but just in case...
Hope it helps, Good Luck

here is a vid of one of the easy spots to get this Achievement