You can't "gain" the rank of commoner. Once a commoner, always a commoner.
Or do you mean that it could be discovered that someone is *not* a commoner?
I think Adventurers are nobles in disguise because they don't want to be a noble yet or part of a realm for that matter. In order to live in society and not be hassled, one must mix in with the crowd - so adventurers pretend to be lowly commoners. No peasants with pitchforks are able to defeat undead champions! Only nobles in disguise.. who want to perhaps be alone, fight heroic battles and find unique items.
Logged
New Harte Family: Eros (Vix Tiramora, EC), Nyx (Fronen, BT), Chance (Avernus, DW), Scopuli (Gothica, Colonies)
Old Harte Family: Hyperion (Aurvandil, DW), William (IVF, BT), Katrina (Fronen, BT), Callandor II (Ohnar West, FE)