Nobunaga no Shinobi

Ninja Girl & Samurai Master

Rescued from nearly drowning in a river, a young Chidori yearns to pay back her savior's kindness. Though her cute and innocent appearance might not show it, she is actually a highly skilled ninja, so years later, Chidori and her friend Sukezou come to serve under the man who saved her—the ambitious warlord, Nobunaga Oda.

As Nobunaga fights off invading forces and sets his sights upon neighboring lands, Chidori is assigned vital tasks to assure victory, such as gathering information or assassinating key figures. Between taking on these important missions and dealing with the colorful cast of Nobunaga's family and servants, the young ninja is always ready to do her best to lead her master toward greatness.

(Source: MAL Rewrite)