This is an original fictional character with no specific historical individual behind her. No 6th-century Frankish witchcraft trial matching this description is attested in the historical record — Gregory of Tours and other 6th-century sources document accusations of sorcery and poisoning at the Merovingian court, but not a formal 'witchcraft trial' in the later medieval/early modern institutional sense the novel's framing evokes. This should be read as the series projecting its own later witch-trial themes backward onto its 6th-century setting rather than as a documented historical event. Ogham itself is a genuine ancient Irish/Pictish alphabet attested in stone inscriptions; 'the Ogham of the Dead' as a specific magical device is an original series invention layered onto that real writing system.