Quagulan

The Quagulan were a species that, in Gallifrey's ancient history, were considered by the Time Lords to be too malevolent or aggressive to remain at large. They were sealed onboard the Consolidator and sent off into the future for later Time Lords to deal with. When the Sild were awoken, they took control of the Quagulan. A Quagulan seized the Third Doctor when he tried to rescue the Master from the Sild's Assembly. The Quagulan were later sent into a deadly point in time by the Master. They wore glittering, knife-edged armour. (PROSE: Harvest of Time)