Forrest is a suave fellow who is not very easy to anger. He is calm, and very smooth when he talks. While he becomes very enraged towards the end of Lego City: Undercover, rage is not really an emotion that is natural to him.
Forrest Blackwell first appears in Lego City Undercover: The Chase Begins after Chase McCain arrests a gang that had been terrorizing Bluebell Mine. During Forrest's initial conversation with Chase, Forrest sounds angry and upset, but then quickly calms down. While it is not obvious unless the player has finished Lego City: Undercover, Forrest Blackwell is clearly involved in the trouble as a crime boss.
In Lego City: Undercover, Chase meets Forrest while escorting him to a play. A crime boss is behind the interaction, referring to Forrest as a special customer, and ordering Chase to provide Blackwell with transportation. Forrest does not recognize Chase from Bluebell Mine and Chase McCain doesn't even begin to act as if Forrest matters. Afterwards, Chase never refers to Forrest as having any kind of large impact at all on crime.
Towards the end of Lego City: Undercover, Chase sees Forrest again, except now it is clear to the police officer that Forrest really does have a strong connection to all of the recent crime in Lego City. Chase also learns that Forrest is in a partnership with Rex Fury. However, the partnership begins to sour when Rex Fury is not able to defeat Chase in a physical fight. Rex Fury uses a robotic dinosaur from the museum as a weapon while Chase battles Rex with his own bare hands. Forrest watches the fight ensue and begins to lose his temper when, even with the huge robot, Rex Fury cannot overwhelm Chase. Blackwell tells Rex Fury that he is worthless at doing his job correctly.
Afterwards, Forrest Blackwell tries to set off a rocket ship into space, which is actually disguised as Blackwell Tower. He is also attempting to destroy Lego City with the fiery exhaust from the space ship. Chase works quickly to build a barrier around Blackwell Tower using technology from Professor Henrik Kowalski. The space ship safely blasts into orbit, unable to harm anyone around it thanks to the successful work of Chase.
Chase goes to Apollo Island to pursue Forrest and Rex in space. The police officer gets inside of a space ship and follows them up into orbit. Once in space, Chase battles Forrest and Rex's hired men on a private space station on the moon. After defeating Rex, Chase loses track of Forrest who disappears to prevent himself from being arrested. While Rex is eventually apprehended after falling from space, Forrest manages to successfully escape.