Sebastian's father is Walter Hyde, a mid-level lieutenant in the underworld until Clevon Brown is ordered to kill him in 1954. Walter convinces Clevon to instead help him stage a coup that puts him in charge of most of the criminal enterprises in the city. Walter makes Clevon his right-hand man and allows the Brown family to move onto the Hyde estate, where Sebastian and Clevon's son Jacob become childhood friends.
The Dead And The Dying
In 1967, Sebastian meets Danica Briggs at a party celebrating Jake's Golden Gloves win and they start dating. When his father discovers that Danica is pregnant with Sebastian's child, he orders Clevon to "take care of it." Danica is forced to have a back-alley abortion (which almost kills her and causes her mother to put her on a bus to Center City) and Sebastian is sent away to college.
Sebastian returns home in 1971 and gets involved in the family business, at first reluctantly, lacking his father's drive for control and willingness to employ brutality to that end. In 1972, Danica returns and seduces Sebastian into revealing details of his operation. Through the ex-thief Hamsunn, she arranges for Teeg Lawless and his partner Willy to rob Sebastian's stash. Jake realizes Danica must be behind the robbery, and publicly slaps Sebastian, to remind him of the terrible things his father did five years earlier.
When Lawless discovers whose money he stole, he approaches Sebastian to return his share of the take. After the humiliation of being robbed by his ex-girlfriend and slapped by his former best friend, Sebastian is ready to embrace his father's vicious ways - he orders Lawless to recover all the money, kill his partner Willy and Hamsunn, and slash Danica's throat, leaving her body in an alley.
The Last Of The Innocent
In 1982, Hyde has Teeg on his regular payroll, sending him to remind Riley Richards of his outstanding gambling debts, and later to warn Riley of the private eye investigating the death of his rich wife. Riley bumps into Sebastian in Criminal: The Last of The Innocent #3, where Hyde comments on his wife's death and sizeable fortune Riley stands to inherit.
Tracy Lawless steals a briefcase of money in Center City, not knowing it is a shipment of counterfeit bills intended for Sebastian. Hyde has his enforcer, Chester, track Lawless down. Instead of killing Tracy, Hyde decides he may prove useful, as his father Teeg had, and puts him to work paying off his brother Ricky's debts.