Overlord, Vol. 6 (manga)

The human realm of the kingdom is headed for its greatest disaster yet! After failing to prevent a daring raid on the Eight Fingers' appalling brothel, the Six Arms are dying for a chance to defend their reputation as the criminal underworld's strongest enforcers. These criminals are notorious for their brutality as much as their strength, meaning the only people who stand a chance against them are the legendary Blue Roses...and one polite, dignified butler. When these thugs make Sebas the first target of their revenge, they may get much more than they bargained for by inadvertently picking a fight with Ainz Ooal Gown!