Nigel E. Kingsgate is a member of the British SAS.
When Majestic-12 planned to initiate a Cold War by launching American Chameleon missiles at various places around the world, and had started a bounty hunt to remove all those who would stop them, Kingsgate was put on their liquidation list.
Kingsgate was part of the SAS squad during an Allied invasion of an Al-Qaeda base. When additional forces arrived and caused chaos, they killed Kingsgate and took his head.
An IG-88 sub-team was taking his head to the Forteresse de Valois to claim the bounty, but en-route Shane Schofield and the Black Knight eliminated them to use Kingsgate's head, as well as a few others, to get them inside the castle.