Short answers, pulled from the story.
Maximilien Robespierre was a French lawyer and statesman, born on the 6th of May 1758 in Arras, who became one of the most influential figures of the French Revolution. He led the radical Jacobin faction, served on the Committee of Public Safety from July 1793, and presided over the Reign of Terror before being arrested and executed without trial on the 28th of July 1794.
In his Report on the Principles of Political Morality delivered on the 5th of February 1794, Robespierre argued that virtue without terror is powerless and terror without virtue is fatal, describing terror as justice made prompt, severe, and inflexible. He framed it as a necessary instrument of a republic under existential threat, not as an end in itself.
Robespierre campaigned for voting rights for all men regardless of property, opposed lettres de cachet, supported full citizenship for free people of colour on the 15th of May 1791, spoke up for Protestants, Jews, people of African descent, domestic servants, and actors, and delivered a speech against the death penalty in May 1791 that Hillary Mantel described as a work of art.
From 1791 onward, Robespierre lived with Maurice Duplay, a cabinetmaker and ardent admirer, at 398 Rue Saint-Honoré near the Tuileries. He moved there after the Champ de Mars massacre when he feared for his safety, having previously lived at 30 Rue de Saintonge in Le Marais.
His principal rivals included the Girondin leaders Brissot, Guadet, and Condorcet, who were arrested or purged starting in 1793. Georges Danton and Camille Desmoulins, once allies, were arrested on the 30th of March 1794 and executed on the 5th of April. Hébert and around twenty of his followers were guillotined on the 24th of March 1794.
On the 9th of Thermidor, Year II, deputies in the National Convention who feared they would be next turned against Robespierre. He was arrested along with around 90 others. Unlike those who had faced the Revolutionary Tribunal, he was executed without trial on the 28th of July 1794, aged thirty-six.