The Kept Man of the Princess Knight, Vol. 3 (manga)

Grey Neighbor’s never been a place for good people, but a wimp like Sterling getting himself caught up in the drug trade is something Matthew never expected...Having sworn to help Arwin stay clean, Matthew is a one-man army fighting the spread of Release through town. Sure, he might be a pathetic kept man, but there’s no line this legendary retired adventurer won’t cross when it comes to keeping her safe. As their story reaches its conclusion, Matthew’s body and code are pushed to their limits. But when the dust finally settles, what will be left for the sunlight he’s cursed all these years to shine upon…?