Derek "Frost" Westbrook

Staff Sergeant Derek "Frost" Westbrook is a Delta Force operator assigned to Team Metal, operating under the command of Sandman. Frost is one of the playable characters and one of the main protagonists in Call of Duty: Modern Warfare 3.

Delta Force Sergeant
Frost participated in the Battle of New York during the events of "Black Tuesday" and "Hunter Killer". His team, Metal, was assigned to destroy a Russian Electronics Jammer on the roof of the Stock Exchange. Facing heavy resistance, Frost and his team manage to disable the Jammer, evacuating aboard a Black Hawk helicopter. They are then pursued by a group of Mi-28 Hind gunships in the skies above New York.

Metal Team is then grouped with a squad of Navy SEALs to take control of a Russian Submarine (acting then as a command vessel). Frost and Sandman sneak aboard the sub and re-program the missiles to launch on the Russian fleet, effectively crippling Russia's seaworthiness and forcing them to retreat as Frost and Sandman make their escape via Zodiac.

Rescuing the Vice President
Their team was later assigned to a hostage situation in Hamburg, Germany involving the Vice President. They get the Vice President and head to Paris, France to capture Makarov's bomb maker Volk under intel by John Price. They received orders from Overlord to rendezvous with and provide backup to the GIGN forces led by Sabre. After meeting up, they carry out their orders of capturing Volk alive.

Assisting the GIGN
On their way to find Volk they are met with heavy resistance from Russian soldiers and armored vehicles, but thanks to assistance from an AC-130 gunship in the airspace they were able to locate Volk, which was hiding in the catacombs. As Volk manages to run away, Frost, his team and the GIGN fight their way to pursue Volk which gets away in a car. Frost's team managed to get in a van and chase Volk throughout the streets of Paris. They managed to apprehend Volk and received orders to take Volk to the extraction point. However, it was compromised and they had to get to the secondary extraction point, which was near the Eiffel Tower. Receiving air support from the AC-130, they managed to get Volk out of the battlefield.

Finding Alena Vorshevsky
Frost's last mission was to rescue the Russian President's daughter Alena Vorshevsky, who was hiding in Berlin, Germany. However after fighting through the city to save her, Alena is captured by Makarov's men. It is unknown why he was not with Sandman and his other teammates in "Down the Rabbit Hole".

Trivia

 * If the player looks at his gloves they will see the logo for Oakley Inc.
 * The way Frost looks at his hands in "Scorched Earth" is similar to the way Ramirez looks at his wounded hands in "Of Their Own Accord" and "Second Sun", which is also similar to the scene in "Vendetta" when Dimitri Petrenko looks at his wounded hands while trapped under a burning board.
 * Frost is the sole survivor of Delta Force's Team Metal.
 * Frost is the only member of Team Metal to have his full name revealed.
 * In Multiplayer, there is an emblem of Frost.
 * In the cutscene in "Black Tuesday", in Sandman's dossier, it is incorrectly stated that Frost is a Staff Sergeant, when he is always a Sergeant.
 * Frost is the only playable character in the Call of Duty: Modern Warfare 3 campaign to use an ACR. He uses an ACR with Hybrid Sight in "Scorched Earth". This level is the last one he is seen in, and also the only time where the ACR is usable in the campaign, in contrast with the Task Force 141 campaign of Call of Duty: Modern Warfare 2, where the ACR is extremely common amongst the members of the 141. This is also the second time he uses a Hybrid Sight on a weapon, the first time being "Black Tuesday", where he uses an M4A1 with a Hybrid Sight.
 * He is the only member of Team Metal that is never seen using a Desert Eagle.
 * In many missions and in multiplayer, it is possible to see randomly generated soldiers with Frost's character model. Special Ops has the players always wearing Frost's model, except in the 141 style missions or Milehigh Jack or the mission Hostage Taker.
 * In the mission "Goalpost", when Frost climbs out of the tank after it falls through the floor in the parking garage, Frost is shown to be wearing a MultiCam jacket, but ACU pants.
 * In multiple Special Ops missions, the player is addressed as "Metal 0-4", Frost's callsign, which may mean that Frost is a playable character in Special Ops missions, outside of Survival Mode.
 * Frost's signature weapon appears to be the M4A1 with varying sights and attachments, as he uses one in "Black Tuesday", "Bag and Drag", and "Goalpost".
 * Frost is the only member of his team to use a SMAW. He is seen using it in "Goalpost".
 * Frost's role in his team is left unknown, Grinch is most likely the Designated Marksman, Sandman and Truck are the commander and second in command/automatic rifleman respectively. Frost appears to be either the "jack of all trades" considering his various roles in the game or a gunner considering he mans the Blackhawks minigun during Metals exfil in Black Tuesday and takes over the minigun of Rhino Two when Carter is killed on Sandmans orders. He could also be the demolitions expert/grenadier, considering he has a SMAW in "Goalpost", and uses Thermite to destroy a jammer in "Black Tuesday", and also has an XM25 with him in "Black Tuesday" as well.
 * It is likely that Frost and Sandman are good friends, considering that Sandman took him along without the rest of Team Metal to go rescue the Vice President, although it is also possible that Grinch and Truck were simply unavailable.
 * According to the credits, Frost and Sandman were present for the Operation Kingfish video, but for whatever reason, Frost isn't in the photo that is seen in the credits of Call of Duty: Modern Warfare 3, along with Gary "Roach" Sanderson, who was the main protagonist of the Task Force 141 campaign in Call of Duty: Modern Warfare 2, who was also present for the operation. This may be due to both of them being playable characters or possibly not being present during the time in which the photo was taken.