In 2014, a terrorist organisation known only as 'The White Masks' starts gaining prominence on the international stage with a number of unified attacks on nearly 18 first and second world capitals. With an unclear motive, and the capability of attacking anywhere in the world at nearly any time, without regard to their victim's age, race, religion or nationality. They became the subject of a number of Counter Terrorist strikes and investigations, turning up with minimal leads despite casualties and arrests. The world started massing their knowledge together, despite previous grudges.
In early 2015, Team Rainbow was reactivated under UN Supervision, after almost 5 years dormant. In the same period Cambridge University came under a biological attack by the White Masks. While Team Rainbow responds within the hour, and removes any and all physical threats from the University's library and nearby dormitory, casualties still reach into the hundreds due to the biological agent used in the attack. Similar events would continue for the next three years.
It is now October of 2018. Three years into Rainbow's mission, and while they remain at work, they have grown to encompass over 40 operators from over 13 nations. All of them dedicated to stomping out the White Mask Threat.
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