Sengoku era, or Warring State Period of Japan, was the period of chaos before the foundation of Edo Bakufu. The constant chaos led to the lack of official historical record(ones produced by government), occasional brutality, poor lives of peasants, and many tales of heroism at the same time. In fact, some of the historical figures from this period appear in Japanese pop culture occasionally, especially Oda Nobunaga, who was voted as the most popular historical figure by Japanese. Considering this massive influence on pop culture, it would be interesting to observe the major figures in this period of Japanese history and see how their influences still manifest.
One thing to maybe look at is the impact certain historical figures had during the Sengoku Era i.e. the battles they took part in, the significance of the battle, etc.
For example, one could look at the Battle of Okehazama and how that battle cemented Nobunaga's legacy in Japan. – Xperimance6 years ago