|“||Never fear a storm, Jason, it's your father saying that he loves you.||”|
–Beryl, to Jason during his vey childhood
Zeus: Birth of Thalia
Beryl Grace dated Zeus during the eighties, when she was a TV starlet with a "big poofy eighties hairdo", and their relationship resulted in the birth of Thalia Grace. However, Zeus eventually had to leave her to return to his duties on Olympus. Beryl was unable to accept it, as it was like the ultimate achievement for her to attract the king of the gods. This blow to her ego caused her to turn to alcohol and pulling stupid stunts, which not only led to her life and career being ruined, but also resulted in her being unable to have a decent relationship with her daughter, Thalia.
Jupiter: Birth of Jason
Seven years after Thalia was born, Zeus returned to Beryl (this time in his Roman form, Jupiter), which Thalia thought was because he felt bad about ruining Beryl's life. However, according to Hera, the true reason Beryl managed to snare Zeus' affections a second time was because she imagined him in his Roman aspect.
He stayed for awhile and Beryl improved her behavior, loving the attention Jupiter gave her. The two also had another child, much to Juno's anger. In order to appease the goddess, Jupiter decided to name his new son Jason, after Juno's favorite mortal. Beryl had not agreed with the choice of name initially, but was forced to give in to Jupiter's insistence.
Raising her ChildrenHowever, Jupiter eventually left them again, and Thalia believed it was because he could no longer tolerate Beryl's constant demands to either let her visit Olympus, or to make her immortal or eternally beautiful. When he left for good, Beryl became increasingly unstable, blaming Hera for the monsters who had started attacking Thalia, and claiming that Hera was coming for Jason as well. Thalia confessed that she did not know whether or not to believe her mother, and she had only stayed with her because she did not trust her to look after Jason properly.
Two years after Jason was born, Beryl took the family on a vacation near the Wolf House. Beryl told Thalia to go get the picnic basket from the car. While she was gone, Beryl offered Jason up to Juno as a peace offering. When Thalia returned, Beryl told Thalia he was as good as dead as she cried on the stone steps. Thalia had thought her mother had finally lost her mind and searched for her brother, and Beryl had to drag Thalia away, kicking and screaming. Thalia eventually called the police on her own mother, leading to Beryl being questioned for a long time but not being arrested. Beryl then turned on Thalia, claiming she had betrayed her. The mother and daughter argued before Thalia eventually left her home.
Later Life and Death
Beryl only got worse from there. She developed a drinking problem, which grew progressively worse over time, ultimately resulting in a car accident that took her life, two years before Thalia was purged from her tree by the Golden Fleece. This was mentioned in the Titan's Curse.
Thalia, Percy Jackson, and Nico di Angelo are in the Underworld on a mission for Persephone to recover Hades' stolen sword. When traveling through the Fields of Asphodel, Thalia looks around at the faces, looking for her mother, Percy guesses (she could have been searching for Jason too, as at that time, she thought that he was dead). Also, Melinoe appears to Thalia as Beryl, yelling at her for abandoning her. Thalia is shocked by this, and protests that it was her mom who had abandoned her. Percy manages to destroy the illusion by out-smarting Melinoe and Thalia is very shaken up from the experience.
When Prometheus called Thalia by her full name, Thalia Grace, she claimed "That's my mother's surname. I don't use it," indicating that she was on bad terms with her mother. Percy was surprised at learning Thalia's last name, having never wondered about it, stating that it made her seem almost normal.
When Thalia is reunited with Jason, she explains what happened the day he disappeared and mentions why she had run away from her mother. She also tells him how their mother died two years before she was cured and awoken through the Golden Fleece.
Beryl is briefly mentioned by Jason when he was thinking about his father.
Shortly after Jason departs from the House of Hades, his nightmares become much worse, but the one with Hera and Beryl is the worst of all: after Jason dies from seeing Hera's divine form, he sees himself as a baby once again, and his mother kneels beside him and promises to see him again soon. Jason longs for her ghost to stop tormenting him. At the feast at Odysseus Palace, Beryl appears to Jason, telling him she meant to come back to him but was forbidden by Juno and Jupiter to come and see him again. Jason asks her why she was at the feast, to which she proclaims that she wanted life, youth and beauty but was abandoned by Olympus and Zeus. But she remarks that she thinks of Jason as her proud warrior. He works out that his mother, Beryl, is actually a mania, a spirit of insanity that she had been reduced to at her death and afterwards. At this Beryl wants her son to come back to her and that they can be a family together, but Jason refuses, and proclaims that he is no child of hers. To this (and the Greek sign of warding evil that Jason did) she disappears with a hiss or sigh of relief.
Beryl Grace was an extremely selfish person with a constant craving for attention and a ceaseless desire to gain more than what she had already acquired out of an advantageous situation.
Even before she met Zeus, she already had serious problems, such as drinking and constantly pulling stupid stunts to ensure that she was always in the tabloids. After Zeus fell in love with her the first time, Beryl felt like she had made some kind of grand achievement, which clearly caused her to fall in love with Zeus because he gave her attention and her ego grew uncontrollably. Hence, when he left, she was unable to accept it, and her flaws worsened.
When Zeus returned as Jupiter, she relished in the attention he gave her and improved until he left once again, causing her downward spiral. When Thalia called the police on her after Jason vanished, Beryl turned on Thalia, believing she had betrayed her own mother instead of siding with her and agreeing it was the right choice. Her bad habits eventually lead to her death in a car accident as she had been drinking.
Beryl was described to be a tall, beautiful woman with a big poofy eighties blonde hairdo and blue eyes.
In The Sword of Hades, Percy described her as a tall woman with disheveled blonde hair and a stern disapproving face.
In The Blood of Olympus, Jason described her as having hair that was an over-teased corona of dyed blonde curls, blue eyes that gleamed with fractured light, and a scent of lemons and aerosol. She was dressed in a flowery green-and-red wraparound, like the skirt of a Christmas tree, and she had colorful plastic bangles on her wrists. The worry lines around her eyes and the pained tightness in her mouth reminded Jason of Thalia. 
- She is the only known mortal to parent both a Greek and a Roman Demigod.
- Even though Beryl is mentioned multiple times in both series, her first actual appearance is in The Blood of Olympus, since the ghost in The Sword of Hades is Melinoe in disguise, not the real Beryl.
- Hera accidentally called herself Beryl in Percy Jackson's Greek Gods instead of Beroe. 
- Beryl is the only character to have been both mentioned in the first book of the first series, and appear in the last book of the second series (where her name is finally revealed).