Diablo III

You get this for defeating the Skeleton King in Act I.

Once you get to his throne put the crown on him and he will awaken. The boss is not that tough. He swings a giant mace around the area, occasionally warping around.
Avoiding his attacks is pretty simple because they are very slow. Simply move or roll away and you should be fine. The Skeleton King makes the boss fight much easier by summoning skeletons throughout the fight. Wiping them out will result in some much needed red orbs.

When his health gets low he becomes much more aggressive but it shouldn't be too difficult to outlast him, especially on normal. Just watch out for his teleport attack, focus on flanking him and he should be a pile of bones in no time.

As long as you explore all over the Cathedrals, this achievement shouldn't be miss-able, especially since its a part of the main mission. This achievement also unlocks if you play on harder difficulties :)

In Act 1 there's a mission called Reign of the Black King. In this mission you must pass through the Cathedral's 4 levels and then enter the Royal Crypt. After the Royal Crypt you will come upon the Crypt of the Skeleton King.

In my first try I died on Hard Mode because since it takes a while to get to the crypt (1 hour - 1 1/2hrs?) my armor was damaged, so before fighting the boss, i advise you to return to town and repair your items.

Be careful of the Skeleton Kings attack if you are on a higher difficulty as it is powerful and if your armor isn't strong enough or if you didn't repair it then you will die in 1-2 hits. Otherwise he's pretty slow and teleports alot. Also keep on the move because when he summons his people to attack they will try to appear around you and trap you if you are in one spot.