Knights of the Sky is the first browser-based MMORTS title from popular MMORPG publishers, Atlus Online. The game includes many of the much loved features of the typical MMORTS title but also has a few unique aspects that set it apart from the typical browser-based MMORTS game.

When you first start Knights of the Sky, you're given to the choice of selecting 1 of 2 nations to represent, Hales Empire or Anjelou Federation. The factions represent good and evil from their own perspective, with both factions having access to similar content. The main purpose of the factions is to create a more intense PvP environment.

Your character, a Lord, is the main hero of your army. You can assign troops to your Lord, making him more dangerous in battle. Lords level up as they progress through the game and defeat opposition armies. With each level they're awarded a talent point to spend on various available talents. There are a large amount of talents to choose from, some will allow you to gain more experience per fight, others will increase the damage of specific units such as cavalry and foot soldiers. Using your talent points to compliment your play style can have a great effect in close battles. You can also win, buy and find special gear and equipment for your Lord, increasing your armor, damage or health points.

The most appealing aspect to game is the turn-based battle system. Unlike other RTS titles where the fights are automatic, Knights of the Sky allows you to take total control over each battle by issuing each unit with various commands such as offensive, defensive and movement. This means that each fight is skill-based and not just dependent on the amount of troops you have. The game also allows players to toggle auto mode if the fight is too easy to waste time with, allowing your troops to kill the enemy without any input from you.