Updated 04-05-2016 01:20 AM
To unlock this achievement you simply need to kill 500 Kobolds in the game. There is no real need to grind out the kills as this achievement unlocked naturally for me as I was completing quests and leveled up to 40. You can also check your status by bringing up the menu, tab over to Quests, access the journal menu, tab once more to achievements, and scroll down to Slayer.