General Reynier de Jarjayes is the head of the Military in France, a member of the Royal court, husband of lady Emilie de Jarjayes and father of Oscar and her sisters as well as the grandfather of Oscar's niece and nephew from his daughters.
In the prequel to Rose of Versailles, he was a young widow who fell in love with a young Emilie, who was engaged to another man at the time. But after Emilie's mother learnt this she learnt the truth and gave the young couple her blessings to marry.
After having five daughters he was hoping to have a son to carry on his military work when he retires, but when Oscar was born he was deeply upset when he found out she was a girl, as he desperately wanted a son to take over the Jarjayes military legacy as women could not keep their maiden names. But then he got an idea, out of desperation, he declared that he will raise Oscar as a boy and make her into a filial 'son' that will bring pride to her father's military legacy. What General Jarjayes didn't know was that him raising Oscar as a boy would have consequences as he unknowingly sealed his daughter fate when he declared to raise her as a boy as it will get her killed in the Revolution when she grows up.
As Oscar got older, she had a very poor view of nobles and believed that most of them are criminals escaping justice with their titles and at the beginning she did not want to become a palace officer due to this. This causes conflict with father and daughter and general Jarjayes would physically abuse her for saying those things, including when she fought Victor and when she left her house when she was under house arrest from Marie Antoinette. In those early years of Oscars life, he was an arrogant man who blindly following the kings orders and Andre, Andre's grandmother and Oscar saw his temper and thought to believe to be insane.
His personality began to change when Oscar left the palace to join the French army, at first he was furious his daughter left the Royal guard, which was a honor to his family, but when he learns she got her heart broken from a man and that she went to a ball in a dress for the first time, General Jarjayes realizes the pain he put his daughter through and that raising her as a boy was a terrible mistake as he believes he made her feel she had to deny her female gender and her feelings as a woman. When he called her to his study he apologized to her for how he abused her and that he should never have made her be a Royal guard in the first place and should have just accepted her as a girl since birth and raised her naturally as a woman like he did her sisters, even crying a bit as he shown his daughter how remorseful he was. Oscar says that's not the case and says she is comfortable with her feminine side, with that General Jarjayes says that she must meet the men at the party to find a husband so she could finally live as a woman as her father's way of making up to her for all the years of putting her through a difficult life as a soldier. But when she attended she dressed as a man and left, General Jarjayes was not angry but actually cried, believing it was to late and he completely ruined his daughter's chances of living a normal life as a woman with a husband and family, and tearfully admitted that he was a terrible father to Oscar.
When Oscar and the French army fought against soldiers of her father's friends who were fighting of rebels, General Jarjayes was told to do something about his daughter. Knowing that Oscar's act would be seen as rebellion and that she could be executed for it, he decides to give Oscar a mercy killing to save her from a brutal death the king would give her and then kill himself to join her in the afterlife, only to be stopped by Andre who tells General Jarjayes that he is in love with Oscar and wants her as his wife, angering the man as he believed noble only marry other nobles. But all three were spared thanks to Marie Antoinette pardoning them, at that point General Jarjayes realized that his daughter was right all along about other nobles being unjust and because of social class the people and France were suffering and realizes Oscar was in love with Andre as well.
Despite knowing the truth, he decides to remain faithful to the crown till the end, believing it can still be fixed. Before he left, General Jarjayes gave his blessing to Andre to be his son-in-law, regardless of him being a commoner and begs him not to die. The last scene with General Jarjayes is him drinking wine in front of his daughter's portrait, awaiting her return until Andre's grandmother gives him a letter from Oscar saying thank you for raising a daughter like her, he became upset as he realizes his daughter will be taking the front line and can get herself killed and yells that he will not let her do that, but will soon find out his daughter has tuberculosis and will eventually die in a year regardless.
After the fall of Bastille, General Jarjayes tried to remain faithful to the monarchy until Marie Antoinette tried to escape house arrest, because of that act he lost all respect for the monarchy and for the queen his daughter served and lost her life for because of Marie Antoinette's negligence that caused the Revolution that got his daughter killed. In real life, when Marie Antoinette and Louis were imprisoned and were to be tried, he left France and went to Italy to serve in their military, and in 1794 he and his wife had to get divorced for convenience so she would be safe from execution from the people of France while he was in Italy because of his loyalty to the crown, until they got remarried in 1797. In a side story with Fersen and Marie Therese, his wife died in 1790 from a broken heart from their daughter's death, something he blamed himself for because of him raising Oscar to be a solider that led up to her death.
He died in 1822.