Andrew "Andy" Darden was one of the firefighters in Truck 81 at Firehouse 51. He was a close friend to Matthew Casey and Kelly Severide . Andy died in the Pilot episode when the vent was unsuccessfully established in the burning building and he was engulfed in flames. He and Heather had two sons together, Ben and Griffin.
Andy was shown as a person with a sense of humor. Often cracking jokes or being funny.
casey: Andy and casey were very close since he put Casey in his will to take care of his sons if him and Heather both perished.
severide: Andy and severide were close friends. Andy severide and casey often hung out.