Hunter Brawn was laundering lots of money through the bank of which Jubilee's (Jubilation Lee) father was the president. When Mr. Lee threatened to go to the police, Mr. Brawn had both of Jubilee's parents killed. Later, through her own investigative work, Jubilee came to the conclusion that Hunter Brawn was responsible for her parents' murder. She sought revenge on him by interrogation, stealth, and hand to hand combat. With the help of her Generation X teammates, Mr. Brawn was subdued. During the confrontation, Hunter Brawn's warehouse was massively damaged by Jubilee's energy blasts.
Mr. Brawn was a power hungry and wealthy individual, until Mr. Lu, an old employee of Mr. Lee's who was in on the whole thing, confessed to the police. This, combined with Jubilee's revenge, led to the arrest of Mr. Brawn.
Hunter Brawn told his grandson Tristan Brawn not to worry, that his lawyers would get him out of this, to which Tristan solemnly replied, "No, they won't."
Tristan left his stunned grandfather, who sadly watched him leave. It's unknown whether the two have spoken since.