Louis Valentin

Louis Valentine (ルイ・ヴァレンタイン), the Pope Emperor of Ruberios is a subordinate of Demon Lord Luminous Valentine and her proxy in controlling the citizen of Ruberios, while his twin brother Roy Valentine plays the role of the evil Demon Lord to unite the populace of Ruberios under Louis.

Trivia

 * Despite both Roy and Louis having the Surname "Valentine," there is a subtle difference between theirs and "Valentine" of Luminous in the Japanese version. While the brothers' surname is spelled ヴァレンタイン varentain, the surname of Luminous is spelled バレンタイン barentain both which are usually transliterated into "Valentine." The most likely reason why that is the case is probably to prevent their surnames from being identical, which would have made the world consider the brothers as Luminous "equals," like in the case of Rimuru and Veldora sharing the "Tempest" surname.