In AI War, nearly all units have a Mark level. This level, often abbreviated "Mk", is always displayed as roman numbers and ranges from I to V (1 to 5). The mark of a ship is a general sign of its power. While an individual Starship is often more powerful than a single fleet ship, some MkV fleet ships are comparable in metal cost, firepower and resilience with MkI starships.
- Mark I is displayed white and there is an option to not display it.
- Mark II is displayed white.
- Mark III is displayed with a dark red outline.
- Mark IV is displayed with a bright red outline.
- Mark V is displayed with a bright purple outline.
Mark level has a technological meaning. Due to their recent debacle, Humans begin with only MkI units and can upgrade most of them with Knowledge up to MkIII. They can't research MkIV units by themselves; they need to capture advanced AI Factories and Starship Constructors in order to access MkIV. (Only Turrets can be researched up to MkIV without the need of AI technology.) The MkV level is reserved to the AI players; they use them almost exclusively to defend their Homeworlds. Only by capturing specific Core Fabricators can Humans access specific MkV units.
Several units have only one version at one mark level. For example, the Dire Guardians are only MkV and there is no lower version of them. On the other hand, other units, such as the Energy Collector, are only MkI.
Power and cost are not linear with mark. Generally, the damage scales linearly with mark but often not precisely. The Metal cost often scales as if MkI was ½ and MkII through MkV were 1 to 4. For instance, the Standard Fighter cost from MkI to MkV are 400, 800, 1,600, 2,400 and 3,200. The Energy consumption is generally constant (MkI fleet ships cost is halved), which means high mark units are more energy-efficient. Stats like armor and armor piercing often scale with mark; others like range, speed and rate of fire often don't. The ship Cap is constant through mark, with very few notable exceptions.