Roy Valentin/Chronology

Octagram Soars Brightly
Roy Valentin was first seen acting as the Demon Lord Valentin with a maid, who was Luminous in disguise, during the Walpurgis Banquet. After Veldora Tempest revealed his and Luminous' true identities, Luminous ordered him to go back and defend the inner sanctum of Ruberios.

On his way back he encountered Laplace, who had just been repelled from the Inner Sanctum by Hinata Sakaguchi. At first, Roy corners Laplace despite being weakened by the new moon, but after Roy starts mocking the deceased Clayman, Laplace gets enraged and kills Roy by using the strength and techniques that Laplace keeps typically concealed.