Short answers, pulled from the story.
Gnaeus Octavius was a Roman senator and member of the Plebeian gens Octavia who served as consul of the Roman Republic in 87 BC alongside Lucius Cornelius Cinna. He was the son of a consul and the nephew of Marcus Octavius, who had opposed Tiberius Gracchus's reforms in 133 BC. He was also a third cousin to the father of the future emperor Augustus.
Gnaeus Octavius was beheaded in 87 BC by Gaius Marcius Censorinus after being captured on the Janiculum Hill. Censorinus brought his head to Cinna, who had it nailed to the Rostra in the Roman Forum. Octavius refused to flee when Censorinus and a small cavalry force stormed the hill.
The two consuls clashed in 87 BC over Cinna's proposals to enrol newly enfranchised Italian allies across all of Rome's tribes and to recall Gaius Marius from exile. Octavius, a conservative senator, strenuously opposed both measures. The dispute escalated from Senate debate to street violence in the Roman Forum, ending with Octavius driving Cinna out of Rome.
Before taking office, Octavius and Cinna were made to swear an oath to uphold the constitutional changes introduced by the outgoing consul Sulla and not to strip Sulla of his command of the First Mithridatic War. Described as scrupulously religious, Octavius kept this oath throughout his consulship.
Octavius lost 6,000 troops during the fighting against the Marian forces that briefly took the Janiculum. His ally Pompeius Strabo lost roughly 11,000 men, through both combat and a plague running through his army. Strabo's subsequent sudden death left Octavius commanding the demoralized combined remnants.
Lucius Octavius was the son of Gnaeus Octavius the consul of 87 BC. He went on to hold the consulship himself in 75 BC, roughly twelve years after his father's execution during the fall of Rome to Cinna and Marius.