Short answers, pulled from the story.
Vagdavercustis was a Germanic goddess known only from a dedicatory altar inscription found in Cologne, Germany, dated to around the 2nd century CE. She was most likely a native Germanic or Celtic deity honored using Roman ritual imagery.
The meaning of Vagdavercustis remains unclear. The element -vercustis may combine the root wer-, meaning man, with a verbal noun reconstructed as *kusti-, meaning choice, compared to Old Icelandic mann-kostr, meaning male virtue, while the prefix Vagda has no clear translation. One later reading takes the full name to mean protectress of war dancers, casting her as a war goddess.
The altar to Vagdavercustis was found in Cologne, Germany, and is now kept in a museum there. It dates to around the 2nd century CE.
The altar was dedicated by Titus Flavius Constans, a Roman citizen serving as prefect of the Praetorians. The inscription reads that he dedicated it to the goddess in his distinguished memory.
Some evidence points to the Batavians, a Germanic tribe that the Roman historian Tacitus placed around the Rhine delta in what is now the Netherlands. They are believed to have worshipped Vagdavercustis in the region between the present-day Netherlands and Cologne.
Outside Lower Germany, the only known trace of her worship is a votive inscription dedicated by a Batavian auxiliary soldier stationed in Pannonia. No other dedications to Vagdavercustis have been found anywhere else.