Press B to open Stats, then look for the class panel in Lantern Build. Your class is derived from your allocation across Willpower, Intelligence, Energy, and Vitality; its name and bonuses appear alongside your attributes.
Unformed means a class has not yet formed. It is a starting state, not a lower-ranked combat class. Continue allocating points toward the attributes your build needs and check the class panel as you go.
Your class and your Corps are separate systems. Specialist and Vanguard describe attribute-based combat roles; Corps refers to your ring faction. See the Corps guide for ring choices and how their separate saves work.
