"ROUKIN" may be a specific fansub group tag or a localized abbreviation used in file-sharing communities.
A common anime series with "Akuma" in the title where "11" would represent the eleventh episode. Akuma-ROUKIN-11-480p.mp4
A classic anime series (original 1989 version or 2023 Netflix revival). "ROUKIN" may be a specific fansub group tag