Lorgar Aurelian (also known as Lorgar) is a Demon Primarch of Chaos Undivided and servant of the Dark Gods of Chaos in the Warhammer 40k universe. Lorgar is the Primarch and former leader of the Word Bearer Chaos Space Marines Legion. A genetically modified super-soldier Lorgar was once a herald of the Emperor working to unify humanity under the Imperium's galactic spanning standard. Unfortunately, Lorgar's pious and devout nature, coupled with what some would consider unjust treatment from his father and brother Primarchs led him down a dark path. This pilgrimage afforded Lorgar new insight and abilities, which would ultimately turn humanities ambition on its head and result in a devastating conflict that would last millennia.
Many aeons ago, when Lorgar was still fundamentally human he was shown to be a fairly kind and caring individual back on his home-world of Colchis. Due to his upbringing upon the religious world, Lorgar possessed a deep passion for religion and faith, coming to view it as a fundamental truth for humanity. Seeking this truth with a zeal he passionately defended his views with a righteous vengeance. He also proved himself a very intelligent and capable man, as demonstrated by his ability to leave Colchis under the capable leadership of trustworthy regents, when he left with the Emperor of Man Kind to take part in the Great Crusade.
Never the less, hints of his dark future could be seen from very early on. Though he himself did not start any confrontations in his youth, always letting others throw the first blow as it were, whenever the situation called for it Lorgar and his devoted followers were unafraid to defend their views with violence. These traits were carried over to his legion, who like Lorgar initially carried out all of the Emperors orders to the absolute extreme with fierce devotion. However, Lorgar was a very staunch traditionalist and late arrival to the Great Crusade, whose legions progress was comparatively slow compared to the other Primarchs. This coupled with his refusal to embrace the Imperial Truth put Lorgar at odds with the Emperor and his brothers, a fact, he would later come to exploit.
Following his pilgrimage and renunciation of the Emperor of Man-Kind, Lorgar became a much darker character. With his eyes opened to the truth, he secretly began to plot with fellow Word Bearers and long-time advisors of his Erebus, and Kor Phareon to open humanities eyes to the existence of the Chaos Gods. The decisions made by these three men heralded the coming of a dark age for humanity. Though Lorgar continued to aid those he viewed as allies, he was a much more fickle person now, aided by the ruinous and destructive powers, utterly ruthless to those he deemed enemies. Lorgar's actions culminated in his ascension to demonhood, at the cost of the eternal division of humanity, the creation of the Chaos Space Marines, and initiating a galactic wide civil war, starting with the Horus Heresy. Since his ascension, Lorgar has retreated deep within the confines of his new home world, allowing others to take control of his legion whilst he himself continues to meditate on the great mysteries and machinations of the Gods he worships.