Self Propelled Guns
Self Propelled Guns, usually called SPGs, are an unpopular class that many teams only begrudgingly accept in their ranks. Their relationship with other vehicle types has been greatly damaged by the events preceding the the Purge. Ever since these events, SPGs tend to receive poor training as the knowledge of the finer aspects of their class was mostly wiped out in the aftermath of the Purge. Even those who remember usually don't share the knowledge in fear of causing another genocide. SPGs are a diverse class in terms of personality and mentality. Especially older models may act nearly or completely emotionless, whereas newer ones come with vastly different personalities. What they all have in common is an internalized sense of shame - some of them cope by inflating their own ego, while others are meek and submissive. A common stereotype is that anyone who is too unskilled to do anything else switches classes to become an SPG. Defenders of the class argue that one needs special qualities to survive as one - concepts that other classes are unable to grasp - and that they are invaluable assets to a team.
Anatomy & Morphology
SPGs usually feature high caliber cannons.
Perception and Sensory Capabilities
They are equipped with a special targeting mechanism (Artillery Sights) that allows them to "see" their surroundings differently.
Civilization and Culture
"Arty" is a name that is given to SPGs very commonly. Even if they have chosen a different name for themselves, their teammates may use Arty instead, depending on how much they respect the SPG. Most SPGs don't like being called this generalized term, but there are also many who don't mind or don't care.
Culture and Cultural Heritage
SPGs were the first class to attain conscience. The old ones - of which none are alive anymore - were still more similar to autonomous killing machines than feeling, sentient beings. Even though the minds of contemporary SPGs are much more advanced, the legacy of the old ones lives on in certain ways; not only the minds of the SPGs themselves, but also their reputation.