WARRIORS OROCHI 3 Ultimate

The description of this achievement is incorrect, as it actually requires you to clear five battlefields in one stage. The contents of each stage are randomized each time you start a new playthrough of Gauntlet and can also be changed by spending five port crystals of the color corresponding to the stage.

The first time you'll have an opportunity to come across a five battlefield stage will be during your 3rd playthrough of Gauntlet when you finally get access to the cyan port crystals. Normally you will come across such a stage naturally by progressing through the levels, however, if you do not happen upon one by the time you make it to the fourth level, you can always gather five cyan port crystals to change the contents of a stage.

The easiest way to get the above mentioned crystals would be to use a formation with the "getaway" skill and keep replaying a single battlefield stage. Then, once you have the crystals, simply save, change the contents of any cyan stage, and if you don't get the five battlefields just quit to the main menu and try again.

Once you find the stage that you need you can simply run through it the way you normally would, which will also give you a great opportunity to pick up the "One Warrior Vs. Ten Thousand" achievement if you haven't already, as you only need to get 2500 kills per battlefield, or you can just use the aforementioned "getaway" skill and finish the whole thing in under a minute.

Whichever way you decide to do it, it's a very simple achievement, it just takes some time before you get access to five battlefield stages.