It is commonly accepted within the Towergirls community that the concept of a sole canonical universe does not exist. Instead, offshoots of a central (or several central) settings are used to explain the many interpretations, re-interpretations and other alternating views regarding characters, locations, rules and etc. prevalent in the variety of Towergirls projects.
Examples of media with differing central settings (where the universe has been heavily reinterpreted from the norm to fit an internal narrative) include Markydaysaid's TowerGirls series.
Central Canonical Universe
Despite the lack of a true centered canon, each setting (both central and off-shoot) will always contain a mishmash of narrative elements vital to the Towergirls universe, including (but not limited by): the existence of a solitary hero or group of heroes, the damsels in distress and an antagonistic entity or group. These primary forces build the foundation of many of the stories told within Towergirls directly and indirectly.
A central setting built by Gats, the creator of Towergirls. This is not the Central Canonical Universe, though the majority of off-shoots extend from this interpretation. The Gats-Canonical Universe has a fixed setting and story revolving around the Loyal Knight and the Dragon Kingdom. This central setting has gone through many iterations since its conception, and continues to do so through the updating of characters, locations and other design elements.
Examples of media that aim to stay as faithful to the Gats-Canonical Universe as possible include Towergirls: Subtitle Pending and this Wiki.