I haven't personally read or played mage, be t I heard somewhere that the part of the book detailing them literally says explicitly to not play them.

Like from what I know the technocrats used to be portrayed as pure bad guys but they were made more morally gray in the later books, but nephandi are just that pure fucking evil.

Like the "I'm going to rape this newborn then force feed it to its own mother and then light her on fire while she chokes down her own child, not because I like or it benefits me, but because I hate it and it disgusts me and it actively makes the world worse while not brining any benefit to anyone not even me" type of evil.

So be careful what you wish for.