I found an interesting translation from the Second Fanbook with some tidbits I haven't seen before:
The Shinobi World War Secret Files (pp. 112–115)
Hidden files of fierce battles, now revealed——
The Shinobi World War Secret Files
—The Shinobi World Wars—
——This is the history of the most sinful and blood-smeared wars of the world of shinobi…!!
↓ Without a doubt, the shinobi world wars were hell!! Even the surviving shinobi were heavily affected…!!
[picture of Itachi amongst the destruction caused by SWWIII]
It has been about sixty years since the birth of the 'Five Great Shinobi Countries'. The history of the shinobi's wars has been repeated again and again. Amongst them are the 'shinobi world wars', which involved the entire shinobi world and led to many casualties. These wars broke out thrice and brought together all of the power held by the various countries' hidden villages. On top of the innumerable amount of corpses, today's stability was built.
The conflicts of the Great Five Shinobi Countries called out the troubles of the entire shinobi world!!
Playing a central role in the shinobi world wars, the countries called the 'Great Five Shinobi Countries' hold massive funds and resources. In exchange for economic support from the great countries, like goods and money, the various hidden villages put everything on the line to fight as their military force. Within the shinobi world, the influence of the five great countries was tremendous, and the great countries' intentions spread to all countries and people. Especially the villages that did not receive aid from the great countries were left violently ruined by the war, and because of looting by the aggressors, the damage even reached civilians.
[picture of Yahiko saying he'll change his country and save everyone]
↑ The 'war orphans' lost both their parents to the shinobi world wars. Their many fates were all disastrous…!!
(The Second Shinobi World War)
[picture of the young Sannin]
â†â†“Situated in-between Konoha, Iwa, and Suna, the village of Amegakure, became the site of a bloody battle where the three village fought ruthlessly!!
[picture of HanzÅ]
The seriously wounded Five Great Shinobi Countries ended the First Shinobi World War with an armistice treaty. For a while, there was peace. However, about twenty years after the war, the economic disparity between the countries grew more and more severe. Using the 'expansion of fair interests' as a pretext, war factions began to rise amongst the nations. Territorial expansion through the use of military force grew. The gruesome Second Shinobi World War had begun.
→↓ Tsunade's grief over losing her lover gave birth to the development of present-day medical ninjutsu.
[picture of a desperate Tsunade]
[picture of a dying Dan]
(The Third Shinobi World War)
The damage done by the Second Shinobi World War had been enormous for all nations. Because of a decline in national power, the reign of the Five Great Countries was crumbling. Along their borders, skirmishes with smaller nations broke out all the time. The prolonged war gradually spread its fires far and wide, until at last it developed into the Third Shinobi World War. This war turned into an unprecedented war of attrition, tormenting all nations with a shortage of war potential. Not even excepting a great power like Konoha, very young children were thrown unto the battlefield, losing their short lives.
[picture of waiting Iwanin]
↑ Iwagakure's master hand was their invasion of Kusagakure, which allowed them to advance to the border with the Land of Fire. They were welcomed with an attack by Konoha shinobi!! With the pride and rise or fall of their villages on the line, a fierce battle ensued…!!
//Many shinobi organisations were also created…!! During the great wars, people appeared who formed shinobi organisations, collecting their characteristic military power.
During battles for supremacy, they became useful as valued war potential, but too much power was regarded as dangerous and was even destroyed…
The shinobi who did the best during the wars would be remembered as 'heroes'.
â— Hero biography 1
[Konoha's Yellow Flash]
…Minato Namikaze
[picture of Minato saving Kakashi while tagging Mahiru]
↑→ His high-speed battle techniques, based on 'space–time ninjutsu', could not be seen through, even by skilled shinobi.
[picture of Minato about to kill Mahiru]
â— Hero biography 2
[Konoha's White Fang]
…Sakumo Hatake
→ He was such a powerful man that it was said that even the 'Legendary Sannin' paled before him. He is Kakashi's father.
[picture of Sakumo]
â— Hero biography 3
[HanzÅ of the Salamander]
→ The head of the old Amegakure. Clear-headed and with many techniques under his control, his name was known throughout the shinobi world!!
[picture of HanzÅ]
The world before the shinobi world wars
Before the establishment of the hidden villages, there was an era of unending conflict, called the 'Warring States Period'[1]. During this time, shinobi organisations were little more than armed groups based on clans. The countries, intent on expanding their interests and territory, employed them individually, causing war everyone to go on and on…!!
[picture of a blood-spattered map]
↑ More than eighty years ago, the world was in chaos.
The mystery-ridden First Shinobi World War
The 'First Shinobi World War' was the first great war after the Five Great Shinobi Countries were established. Because the outbreak of the war had thrown the entire shinobi world back into chaos, there are only few records concerning the war. One thing is certain: after the war, many tactics were born from the experiences of the war. These form the foundation of current battles…!!
→ The shinobi killed in the line of duty during the war had their names inscribed on the memorial stone as heroes.
[picture of Kakashi at the memorial]