Tales of the New Teen Titans #2 (1982)

Raven wakes up screaming in her tent from a nightmare. The Titans (in particular, Wally) race into her tent to see what is wrong. She tells them that she dreamt of her father and realizes that in order to come to terms with her dark heritage, she needs to tell her teammates about her origins. Raven's mother was an Earth woman who was seduced by the demon Trigon. After leaving her with child, Trigon abandoned her, awaiting the day when he would return to lay claim to his heir. Pacifist priests from the interdimensional world of Azarath discovered the woman and brought her to their home dimension to care for her. She was named Arella and gave birth to Trigon's offspring which she named Raven. Raven was raised by the spiritual leader of Azarath, Azar. She was denied forming a familial bond with her mother and the magistrates of Azarath decided that she must be denied any emotional detachments less the dark passions of her father's influence should grow in power. When Raven was still an infant, one of the Azarathians, Juris, sought to save their world by dispelling Raven into Limbo. Trigon, always watching from his own realm, intervened and destroyed Juris before he could carry out his threat. When Azar died of old age, she bequeathed the Rings of Azarath to Raven and instructed Arella to carry on with the child's meditative training. As a youth, Raven's empathic powers began to develop, but as she grew stronger, so too did Trigon's influence over her. When she was a teenager, she opened the Great Door at the Temple of Azarath and confronted her father for the very first time. This encounter caused Raven to manifest her soul self for the first time. Trigon told her that this dark aura was the totality of his own essence that had grown inside of Raven ever since she was born. Though she refused to take her place at her father's side, she accepted that Trigon was indeed her father. This was enough to satisfy Trigon for the time being. When Raven was eighteen-years-old, she realized that Trigon threatened all of existence, so she fled Azarath for Earth in the hopes of finding heroes strong enough to combat him.