Regis Lucis Caelum CXIII (Regisu Rushisu Cheramu Hyakujūsansei) is the king of Lucis and Noctis’s father. As the ruling king of Lucis, he safeguards the Crystal and protects Insomnia using a magical barrier called the Wall using the hereditary Ring of the Lucii. Maintaining the Wall drains Regis of his life energy, causing him to age rapidly. In Brotherhood, it is revealed that Regis fought off the Daemon that almost killed Noctis, but the two become estranged as Regis’s health failed to meet the Wall’s energy demands and Noctis had to come to terms with his future as Lucis’s king. He fought against Ardyn in Episode Ardyn, almost dying at his hands. When Regis accepted Niflheim’s peace offer, despite knowing it is a trap, he sent Noctis away from the chaos that would ensue in the events of Kingsglaive. Losing the Ring of the Lucii when it was cut from his hand by Niflheim’s General Glauca, Regis dies fighting the general despite Lunafreya wanting to save him. Regis reappears as one of the Lucii when Noctis sacrifices himself to end the Starscourge and destroy Ardyn, delivering the final blow. (Wikipedia)
