The Hero of Tython (also known as the Hero of Coruscant) was a Jedi Knight who rose up to challenge and ultimately defeat the Sith Emperor Vitiate during the Cold War between the Republic and the Sith Empire. One of the four members of Coruscant Aegis.
The Hero of Tython was mentored by Jedi Master Orgus Din and later came to take on an apprentice of his own in the former Sith acolyte Kira Carsen, who may have also pursued a romantic relationship with the Hero depending on their gender. The Hero of Tython saved Coruscant from Sith forces and also repelled Darth Angral, who attempted to make use of a superweapon called The Desolator.
Eventually, the Hero of Tython's path took them to the Sith Emperor himself, but alas the Emperor was too powerful and the Hero of Tython was overpowered and briefly turned into a subservient minion before eventually being freed from his control by the Force Ghost of Orgus Din.
During the escape from the Emperor, the Hero of Tython recruited an unlikely ally in Lord Scourge, a longtime servant of the Emperor who had in fact been planning on killing him for some time due to recognizing his insanity and his being as much a threat to the Sith as he was to the Republic and the Jedi. Eventually, the Hero of Tython engaged the Sith Emperor in a rematch and after an intense battle was able to defeat him.