Any Terry Pratchett reader will tell you that Chaos was the Fifth horseman but he left before they became famous. The Sixth would have to be Things Not Working, Even After You Give Them A Good Thumping!Six horsemen?
I wonder who the additional two horsemen of the apocalypse would be in the 21st century?
5. No internet access
Chaos changed his name to Ron Soak (KAOS) and became a dispenser of dairy products.