Hah. Quant search results returned only Daimo named restaurants.
Then Daima DragonballZ. (WTF. How is that AI accuracy going?)
And finally. Daimo.
The local feudal lords who were constantly fighting each other.
There was constant early infighting. Hope the series covers that.
The complete islands of now 'Japan' were still not considered up to WW2.
The Ryuku in the South. The farmer Ninja.
The Ainu in the North. Hirsute. Looked like Europeans with beards.
All separate before.
Religion vs warlords. Only the failed Mongol invasions brought them together.
Even the old capitol of Kyoto after Nara had problems with rebel monks in the mountains
https://en.wikipedia.org/wiki/Siege_of_Mount_Hiei
There were three shoguns which consolidated the nation:
-Oda Nobunaga, as ruthless as Chin Shi Huang Ti
-Toyotomi Hideyoshi
-Tokugawa Ieyasu. ~1600. A lasting peace which lasted up until European Cmd Perry forced open the country and gave them Dutch guns to kill each other.. And then back to religion and the Emperor. and modernization.