Lucan succeeded his father, King Brandon, as King of Deltora. Lucan and his son, Gareth, were on good terms with Doran the Dragonlover. Lucan commissioned Doran to travel Deltora and write a book; a traveller's guide to Deltora that would be presented to Gareth. At some point during Doran's travels, Lucan grew very ill, presumably dying from the illness eventually, though Lucan survived long enough for Doran to present him with Secrets of Deltora. Unfortunately, Drumm convinced the king that the book was too valuable to be handled by the young prince, and had it locked away.
Lucan's reign saw the completion of the royal palace, forty years after construction on the building had started. Lucan's chief advisor, Drumm, used the king's trust and resources to hide the Four Sisters throughout Deltora without Lucan's knowledge. Drumm had a platform placed in the palace chapel to hide the Sister of the South, much to the fury of the Ralad builders, who thought the platform was an eyesore. Drumm merely informed them that Lucan wanted the platform to remain, though it is unclear if Drumm was speaking the truth. Lucan's tenure as king also saw the rat plague of Hira reach its pinnacle. Doran the Dragonlover was the first to refer to Hira as the "City of the Rats" after travelling there to while writing Secrets of Deltora.
Manus, having examined the royal palace's original design, was infuriated by the platform in the centre of the palace's chapel. Lief initially thought that the King responsible for the platform's construction was Brandon, Manus denied this, blaming King Lucan, showing Lief a note from Lucan as proof. The note, signed by Drumm in Lucan's name, convinced Lief that the platform hid the Sister of the South.
Lucan, like many of Deltora's rulers, was easily manipulated by his chief advisor and took no notice of Drumm misdirecting the people of Deltora in his name. He seemed to respect Doran as an explorer and friend, but did not share Doran's love of Dragons; Lucan knew that the people feared Dragons and felt that their dwindling numbers were a good thing. Lucan commissioned Doran to write Secrets of Deltora primarily so his son, Gareth, would be properly informed of Deltora when he became king, demonstrating some degree of foresight.
Lucan did not seem to have a good relationship with the Ralads, who thought that he had no eye for beauty and took offence to the changes made to the palace under his reign.
As the King of Deltora, Lucan had access to all of Deltora's resources and guards, but his severe illness weakened his mind and body. For much of his reign, Lucan was not in a proper mental or physical state to rule his kingdom.