1: mobilization of troops
2: blurry roles between civilian and soldiers
(civilians are legitimate targets)
3: refusal to peaceful compromise
(a war only ends when the enemy surrenders)
4: total control of society
(the channeling of a nation’s resources into the war - for example, factory workers who previously worked in the cotton textile sector were forced to build ammunition for WWI)
They must manage a lot of jobs and housing for many including citizens, immigrants, and refugees
In total, the Black Death has killed about 450 million down to 350-370 million in the 14th century.
Hope that helped! :)