Although there are a handful of scenes that highlight the war, Grave of the Fireflies is predominantly concerned with the smaller and often forgotten tragedies that happen during these conflicts.

Source: https://gamerant.com/best-historical-anime-to-watch/

Grave of the Fireflies is Studio Ghibli's third film and the first directed by one of the studio's developers, Isao Takahata.

Source: https://www.cbr.com/cute-anime-families-really-love-one-another/

The opening scene of Grave of the Fireflies shows Seita and several other boys around his age dying at the train station where they were begging for food.

Source: https://screenrant.com/grave-of-the-fireflies-ending-explained/