World War III

World War III (also abbreviated WWIII or World War 3) was the third global war, beginning in 2015, with a great increase in scale by 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 the deadliest conflict in human history.

Cause
Dr. Nakabachi's thesis, Kurisu Makise's research and the PhoneWave (name subject to change) are driving factors behind the war. The United States of America, Russia and SERN all wanted the power to manipulate time and these aforementioned works are pivotal towards the development of a time machine.

Beta World Lines convergence
The international arms race to build a time machine begins in 2010. Valuable assets such as Rintaro Okabe, Itaru Hashida and Kurisu Makise were targeted.

Steins;Gate 0
In 2010, Okabe killed Kurisu Makise and Shouichi Makise stole her thesis. Afterwards, he defected to Russia. Kurisu's personal computer was given to Maho Hiyajo, her mentor at Viktor Chondria University.

Pandora's Box
One year later, in 2011, Maho, 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 gunned down 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, Okabe and Itaru Hashida formed the Valkyrie.

All members of the Future Gadget Lab remain alive by 2036 and took shelter underground. Even Rintaro 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 Shiina off.

>5.7 billion people dead.