Nemesis is the goddess of Traiano
According to Professor Aglaia McClintock, professor of Roman law and ancient rights at the University of Sannio, Nemesis is the goddess represented on the keystone placed at the top of the Arch of Trajan. The divinity is reproduced identically on both sides of the arch and is the central or supporting figure around which the whole system of virtues depicted in the panels rotates, symbol of the reign of the optimus princeps Traiano.
The female figure against a serpentine background, with a long dress draped to reveal the knee, has always been identified as the goddess Rome. According to the new hypothesis, presented in the course of a lesson, as part of the Institutions and History of Roman Law course of the Master's Degree in Law of the Samnite university, the tutelary goddess of Trajan would be Nemesis as Justice.
This alternative hypothesis is dictated by a series of clues including the protruded knee of the headless female figure which is a constant attribute of the Roman Nemesis, a Greek deity imported since the end of the republic to fill the lack in Rome of a personification of cosmic justice.
An interpretation of the 'tutelary' divinity of the arch in terms of justice seems to better explain all the virtues represented on the arch as well as the image handed down in the Middle Ages of Trajan, the only pagan to enter Dante's Paradise for having always put the reasons of justice first. and, therefore, of social peace, to those of war.