Onimaru: Senjou ni Kakeru Itsutsu no Seishun 1990

During the Onin wars in Japan's medieval Muromachi era, five powerful warriors hire out their services to the highest bidder. Onimaru is the leader; Bo handles demolitions; Saru is as agile as a monkey; Osamu is a cool tactician; and Kiri is the sexy swordswoman. The group gains an extra member when Onimaru rescues Princess Aya who naturally falls in love with him and refuses to go away.