Short answers, pulled from the story.
Lucius Junius Brutus was the semi-legendary founder of the Roman Republic, traditionally one of its two first consuls in 509 BC by the Varronian calendar. He is credited with leading the overthrow of the last Roman king, Tarquinius Superbus, after the rape and suicide of the noblewoman Lucretia. Later historians such as Tacitus credited him with "establishing liberty and the consulate."
Brutus feigned stupidity to survive in the court of his uncle, King Tarquinius Superbus, who had already executed a number of Rome's leading men including Brutus' own brother. By pretending to be slow-witted, which is the literal meaning of the Latin word brutus, he avoided the king's suspicion while preparing to overthrow him.
Brutus died at the Battle of Silva Arsia during Tarquinius Superbus's attempt to retake Rome by force. Arruns Tarquinius, the king's son, recognised Brutus commanding the Roman cavalry by the lictors accompanying him. The two men, who were cousins, charged each other and simultaneously speared each other to death.
According to Roman tradition as recorded by Livy, Brutus did preside over the execution of his two sons, Titus Junius Brutus and Tiberius Junius Brutus, after they were discovered as part of the Tarquinian conspiracy to restore the exiled king. Livy notes that Brutus showed emotion during the punishment but did not intervene.
Marcus Junius Brutus, the most famous of Caesar's assassins, claimed direct descent from Lucius Junius Brutus. The conspirator Cassius used the ancestor's memory to recruit Marcus Brutus, reminding him that his forefather had expelled a Roman king. Marcus Brutus minted coins featuring the founder's portrait twice, including on a gold aureus in 42 BC during the Liberators' civil war.
Modern historians regard Brutus as semi-legendary. Almost all records predating his era were destroyed when the Gauls sacked Rome under Brennus in 390 or 387 BC, leaving Livy's much later account as the main source. Scholars have challenged his chronology, his status, and even his existence, though Polybius's report that he signed a treaty with Carthage and dedicated the Capitoline temple is considered among the strongest evidence for his historicity.