Several important concepts define a creature, regardless of species or type.
A creature's structure is it's physical body and the general toughness associated with it. The most common creature in BrikWars, the minifig, is a fleshy thing with a structure level of zero and serves as the baseline going forward. In game terms, the structure and size of a creature contribute to the determination of the creature's base cost in construction points, a means of balancing all the elements of opposing forces in a battle.
A creature's propulsion is its means of movement. Minifigs, for example, have regular ground movement (walking, running, skipping, and the like). In game terms, types of movement cost a certain number of construction points per inches of movement and this cost is added to the base cost of the creature, as determined by the creature's Structure (see above).
Weapons are a creature's most important choice in the BrikVerse, so fundamental is violence to the nature of the place. Weapons should therefore be viewed as extensions of a creature's will. In game terms, each weapon has its own construction point cost, which is added to the creature's base cost, as determined by the creature's Structure.
A creature's mind is its animating force, its intelligence and will. It is this component that ultimately allows the creature to wreak the most havoc and have the most fun. In game terms, a creature's mind costs a number of construction points equal to its size and this cost is added to the creature's base cost, as determined by its Structure.
A creature's cost is its base cost as determined by the multiplication of its size and structure, plus additional costs incurred by its propulsion, mind, and weapons, plus additional costs incurred by miscellaneous abilities (which each have their own associated systems). It is important to note that a creature's cost is not necessarily indicative of its value to the BrikVerse. It is a numerical fate that can be changed, forever altered by good Kanon.