Saikyou no Kurokishi, Sentou Maid ni Tenshoku shimashita

Once renowned across the realm as Albright, the strongest Black Knight, his life took an unimaginable turn when he was reincarnated into a new body. Now sixteen years old and living as a girl named Maria—whose delicate appearance is perfectly complemented by the ribbon she wears—the former fearsome warrior has traded armor for an apron. She currently serves as a maid in the prestigious household of the Marquess of Urband, dedicating her days to attending the young daughter of the marquess, Lady Relena. However, Maria’s quiet life in service is abruptly upended when Relena becomes engaged to the Fourth Prince. This high-profile royal betrothal instantly transforms the once-peaceful estate into a bustling hub of political intrigue and relentless activity. As nobles, officials, and opportunists swarm the household, the area surrounding Maria grows increasingly chaotic. For a girl hiding the soul and strength of the world's most powerful knight, navigating the treacherous currents of aristocratic society while fulfilling her duties as a maid proves to be a challenge far more complex than any battlefield she has ever faced.