Mortal Kombat

This achievement is "Brotherhood of Shadow" - "Discover and fight Hidden Kombatant 4 in Arcade Ladder" for facing (secret) Noob Saibot in the Ladder mode. What you have to do is play on The Temple level, recognizable because of the MK Dragon shaped window in the background, and hope you see Noob standing on the altar in the near background. Then you have to win without blocking.

To make things easier I'd suggest playing on Beginner and constantly quit to main menu and start a new ladder until the first fight is on The Temple. Then, if you don't see Noob, hit start and go to player select and pick your character again. It will load the same fight on the same level. If you accidentally block this method should work as well.

You don't need to beat him, the achievement unlocks at the beginning of the fight.

Good luck!

Edit: If you're going to thumbs down please comment saying why so I can improve the solution.

As Breadly Weapon said, you need to win a match without blocking any attacks, in the Temple level, in Ladder mode. Here are a few things I've discovered in trying for this achievement.

- Normally, there is a priest standing at the altar performing a sacrifice. But when Noob is present, the priest is missing. So instead of looking for Noob, just check whether the priest is there. Noob is off to the side, and dark and hard to see. But you can check for the priest as soon as the stage is loaded, since he's right in the middle.

- You will not fight Noob nor activate the achievement if you win by timeout; you must take away all of your opponent's health before the time runs out. So don't set the round time limit to 30 seconds; set it to at least 60.

- You cannot get this in Tag Ladder; it has to be regular single ladder. Noob will never appear on this stage in Tag Ladder mode.