World War III

World War III (also abbreviated WWIII or World War 3) was the third global war, beginning in 2025. Major powers like the USA and Russia competed relentlessly over time machines. This would spiral into a conflict that would result in 5.7 billion deaths, becoming one of the deadliest conflicts in human history.

Cause
Dr. Nakabachi's thesis, Kurisu's research and the Phone Microwave (temporary name) are one of the driving factors behind the war. America, Russia and SERN all wanted the power to manipulate time and these aforementioned works are pivotal towards the development of a time machine.

Steins;Gate Beta world line
The international arms race to build a time machine begins in 2010. Valuable assets such as Okabe, Daru and Kurisu were targeted.

Steins;Gate 0
In 2010, Dr. Nakabachi killed Kurisu Makise and stole her thesis. Afterwards, he defected to Russia. Kurisu's personal computer was given to Hiyajo Maho, her mentor at Viktor Chondria University. One year later, in 2011, Hiyajo, accompanied by Okabe, hired an anonymous hacker who later turned out to be Itaru Hashida to crack the computer open and see the data inside. However, American assassins intruded their hideout, forcing the trio to flee. Russian mercenaries caught wind of it and gun-downed the Americans along with destroying the computer, delaying America's time machine development. The event would later go down as a terrorist attack in Akihabara.

The situation escalates further as both sides discovered Suzuha's time machine on the roof of the Radio Kaikan building. Armed helicopters arrived at the scene and blasted a hole through the building. Needless to say, the Japanese press dubbed it another terrorist attack.

Course of the war
...

Japan enacts general conscription. Suzuha is conscripted.

Tokyo is leveled and becomes a war zone.

All members of the Future Gadget lab remains alive by 2036 and took shelter underground. Even Rintarou Okabe, who was presumed dead, "came back to life" and was helped back to base by Suzuha. In order to prevent this war, Okabe time-leaped back to 2011 and escorted Suzuha and Mayuri off.

>5.7 billion people dead.