Nobunaga no Shinobi: Nobunaga to Minarai Shinobi
English title: Ninja Girl & Samurai Master: Episode 0
Japanese title: 信長の忍び 第0話『信長と見習い忍び』
Type: Special
Episodes: 1
Source: 4-koma manga
Genres: Comedy
Studios: TMS Entertainment
Duration: 5 min
Rating: PG-13 - Teens 13 or older

Oda Nobunaga saves a girl from drowning one day. She clumsily tells him that she's a shinobi. Instead of attempting to kill him, she swears to serve him one day after hearing his plans to unify Japan.

(Source: Crunchyroll)