With the exception of the main character, who seems entirely fictional (although female shinobi did exist) everyone in the show are real people who did what the show claims they did. In contrast, despite only having three minutes per episode, Nobunaga no Shinobi is able to go into a surprising amount of detail in the conquest of Nobunaga. Unless someone can point me to something more accurate, most Sengoku anime seem to be less retellings of events and more 'dude gets transported back in time to the Sengoku period' or 'figures from the Sengoku period get transported to somewhere else' or 'dude gets transported back in time to the Sengoku period but everyone is cute anime girls' or 'figures from the Sengoku period except they are all cute anime girls get transported somewhere else' But as a student of history (and particularly Japanese history), what really drew my interest in it while binge watching it was just how faithful to the actual events it managed to me. I was first altered to its existence when it started up again for this season (go watch it!). So, if you haven't heard of it, Nobunaga no Shinobi (or Ninja Girl and Samurai Master if you speak English) is a 3 minute gag anime about an incredibly cute female ninja who works for Oda Nobunaga during Japan's Warring States period.