Question: Who is Eudocia (Daughter Of Valentinian Iii)'s sibling-in-law?

Knowledge 1: Eudocia (daughter of Valentinian III)
Eudocia or Eudoxia (439 – 466/474?) was the eldest daughter of Roman emperor Valentinian III and his wife, Licinia Eudoxia.She was thus the granddaughter on her mother's side of Eastern emperor Theodosius II and his wife, the poet Aelia Eudocia; and on her father's side of Western emperor Constantius III and his wife Galla Placida.In the mid-440s, at age 5, Eudocia was betrothed to Huneric, son of the Vandal king Gaiseric (and then a hostage in Italy).This engagement served to strengthen the alliance between the Western court and the Vandal kingdom in Africa.Their marriage did not take place at this time, however, because Eudocia was not yet of age.Eudocia's father was assassinated in 455, and his successor, Petronius Maximus, compelled Eudocia's mother to marry him and Eudocia herself to marry his son, Palladius.In response, the Vandals (reportedly at the request of Eudocia's mother) invaded Italy and captured Eudocia, her mother, and her younger sister, Placidia.After 7 years Eudocia's mother and sister were sent to Constantinople, while Eudocia remained in Africa and married Huneric c. 460.They had a son, Hilderic, who reigned as king of the Vandals, from 523-530.At some time following the birth of Hilderic, Eudocia withdrew to Jerusalem due to religious differences with her Arian husband.She died there and was buried in the sepulcher of her grandmother, Aelia Eudocia. [SEP] Knowledge 2: Placidia
Placidia  was the wife of Olybrius, unrecognized Western Roman Emperor.Her full name is uncertain.The "Chronicle of the Roman Emperors:The reign by reign record of the rulers of Imperial Rome" (1995) by Chris Scarre gives her name as Galla Placidia Valentiniana or Galla Placidia the Younger, based on naming conventions for women in ancient Rome.
Knowledge 1: Eudocia (daughter of Valentinian III)
Eudocia or Eudoxia (439 – 466/474?) was the eldest daughter of Roman emperor Valentinian III and his wife, Licinia Eudoxia.She was thus the granddaughter on her mother's side of Eastern emperor Theodosius II and his wife, the poet Aelia Eudocia; and on her father's side of Western emperor Constantius III and his wife Galla Placida.In the mid-440s, at age 5, Eudocia was betrothed to Huneric, son of the Vandal king Gaiseric (and then a hostage in Italy).This engagement served to strengthen the alliance between the Western court and the Vandal kingdom in Africa.Their marriage did not take place at this time, however, because Eudocia was not yet of age.Eudocia's father was assassinated in 455, and his successor, Petronius Maximus, compelled Eudocia's mother to marry him and Eudocia herself to marry his son, Palladius.In response, the Vandals (reportedly at the request of Eudocia's mother) invaded Italy and captured Eudocia, her mother, and her younger sister, Placidia.After 7 years Eudocia's mother and sister were sent to Constantinople, while Eudocia remained in Africa and married Huneric c. 460.They had a son, Hilderic, who reigned as king of the Vandals, from 523-530.At some time following the birth of Hilderic, Eudocia withdrew to Jerusalem due to religious differences with her Arian husband.She died there and was buried in the sepulcher of her grandmother, Aelia Eudocia. [SEP] Knowledge 2: Gertrude Elizabeth Blood
Gertrude Elizabeth, Lady Colin Campbell ("née" Blood; 3 May 1857 – 1 November 1911) was an Irish-born journalist, author, playwright, and editor.She was married to Lord Colin Campbell, a brother-in-law of Princess Louise, Queen Victoria's fourth daughter.
Knowledge 1: Placidia
Placidia  was the wife of Olybrius, unrecognized Western Roman Emperor.Her full name is uncertain.The "Chronicle of the Roman Emperors:The reign by reign record of the rulers of Imperial Rome" (1995) by Chris Scarre gives her name as Galla Placidia Valentiniana or Galla Placidia the Younger, based on naming conventions for women in ancient Rome. [SEP] Knowledge 2: Gertrude Elizabeth Blood
Gertrude Elizabeth, Lady Colin Campbell ("née" Blood; 3 May 1857 – 1 November 1911) was an Irish-born journalist, author, playwright, and editor.She was married to Lord Colin Campbell, a brother-in-law of Princess Louise, Queen Victoria's fourth daughter.

Answer: Olybrius