DeathSpank

Alright this one is about 25-50% through the game. You'll eventually be given a quest to get some orphans in the town of pluckmuckel. If you follow the path east of the pluckmuckel outhouse, you'll eventually come to a fork. Pick the south path and continue on until you hit a gate. You'll need to enter the cave to the north to get the key.

The key is inside the cave off a demon. Once you go in the gate, follow the path, past the guy that gives you a quest to get packages, and then when you reach the fork, take the path north. You'll enter an orc camp, find sergeant orque and kill him. Achievement unlocked.

You'll find him toward the back of Camp Orqawanga (SE of Pluckmuckel; Name is marked on the map). He will not attack you until you go up and interact with him ("a" button), so I recommend clearing out all the people around him first. He is level 16. Besides his melee attack, he will also blow a horn to call in some reinforcement troops. They're only level 4's so they are more of an inconvenience than a threat. To make things easier, you can set the difficulty to easy (through the pause menu, under "help and options") You can also utilize orbs of invincibility and critical hit potions as well. I can't recall where you can buy orbs of invincibility, but you can buy critical hit and armor potions from bong's shop, across from the taco stand in pluckmucket. Also, make sure to alternate attacks as that increases damage and builds your justice meter faster. So just alternate strikes. I recommend also using one of the weapons whose justice meter function stuns enemies as it will freeze the level 4 troops leaving you to focus on the Sergeant (i.e. attack with "a,x,y,a,x,y" with a stun weapon equipped to the b button and used when the justice meter is full).