Taktički RPG objavljen za PS2, Xbox i GC krajem 2003. godine. Proglašen jednom od najboljih igara za Xbox koju igrači nisu odigrali.
Gladius employs a rigid rock-paper-scissors approach to character classes and combat. There are three main classes of characters: heavy, medium, and light. In the same pattern as rock-paper-scissors, heavy beats medium, medium beats light, and light beats heavy. Barring a large level gap or terrain advantage, this pattern will almost always hold true in any one-on-one battle. There are also the support and arcane classes, which are neutral in the class relationship. Finally, there are several affinity classes, such as the Fire, Water, Earth, Air, Dark, and Light.
To determine the effectiveness of an attack, the game employs two types of swing meters. Most swing meters consist of three segments: blue, yellow, and red. Blue denotes a "miss", resulting in an attack that either misses completely or causes very little damage. Yellow results in a standard damage attack that may still be avoided, depending on the chance to hit given. Red results in a critical hit, which cannot be avoided or blocked and does much more damage. The secondary form of the swing meter is a yellow bar with a small green insert, used for mainly for status-affecting skills. Here, the goal is simply to aim for the green, which will make the skill function properly.
Depending on the swing meter, the player will either be required to press a specific key once to stop the meter on a color, press two buttons in rapid succession to move the meter to a color, or press a specific series of buttons before the meter runs out. Combo meters act in the same manner as the former, but are lined up next to one another, thus requiring the player to repeat the process up to five times.
As the player purchases higher-level skills, using the meters becomes progressively more difficult. While scoring a critical hit using a standard attack is fairly simple, the strongest skills have swing meters which can be quite difficult to use, thus making the points spent to gain them a gamble. Another point to consider is the state of alertness of the player. Given the reflexes necessary to consistently and accurately use the swing meters, and the consequences of missed hits, a tired player will inevitably fare poorer than an alert one.
The game has an option which will run the swing meters for the player with the most common outcome a normal strike. This can make combat much easier or more difficult depending on the skill of the player and the abilities of their school. A player skilled with swing meters can often defeat higher-leveled opponents by capitalizing on critical hits, while a player not using them must rely more on strategy since their fighters will be less effective in battle.