Some cards or skills put markers on constants. Typically, markers are put on agents. Markers provide permanent effects that typically only apply to the constant with the marker. The effect lasts while the constant is marked. Constants with markers are referred to as marked.

The increase marker is the most common marker. It grants agents 1 more attack and 1 more defense. Other markers permanently grant other common skills to the marked constant. Some markers are used to track custom effects relevant to the marked constant.