Legendary

Earliest - and easiest - place to get this achievement is in the first subway level at the start of Episode Two: right after you drop down to the tracks, fire drakes will start spawning out of the fire pit. Whack them with the axe before they curl up, and you can kill them in a hit or two.

About four or five fire drakes will appear at the edge of the fire pit, one after the other; stand on the edge of the pit so you can axe them as soon as they appear.

When the fire drakes stop spawning, head back towards the crashed subway cars. A couple of fire drakes will attack as you make your way through the cars. Finish them with the axe and follow the path to the far side of the subway platform and make your way along the platform until you get to a red sprinkler switch. Throw the switch.

Now, jump back down onto the tracks, where fire drakes will start to spawn endlessly out of the fire pit. Stand at the edge of the pit and bash the drakes as they appear one by one. After a couple of minutes of doing this, the achievement will unlock.

This one isn't too hard to get. I used the axe on werewolves (not alpha males) and those rock creatures that shoot fire at you. Knock out 25 of any creatures and you'll pop the achievement.

When I got this achievement, I got it on chapter 2. After the beginning part of the level where you turn the sprinkler switch, carry on and the game will checkpoint. Continue around until you get to the tracks. Look for your first grate on the level. Upon entering this grate, you are in a thin corridor with one fire drake. Kill this and lie in wait. Fire drakes will jump out of the flames on your left one by one. Kill them as soon as they jump out, otherwise you may take damage. This will eventually fill your health and animus for a nice recharge, and will also earn you this achievement.