2. DayZ kicks off the survival genre in ~2012.
3. A slew of DayZ mods happen. A dev on one mod, playerunknown, creates a Battle Royale inspired mod for DayZ in 2013.
4. In 2016 PU is hired as a consultant for the DayZ knockoff H1Z1 to make a Battle Royale mode.
5. PU is hired by Bluehole to make PlayerUnknown's Battlegrounds, a Battle Royale game. Bluehole uses the Unreal 4 engine from Epic games.
6. PUBG is a hit in early 2017.
7. Epic games sees PUBG's success with their engine so they create a mod of their Unreal 4 building game "Fornite" that implements Battle Royale. It's released for free.
8. It's free, cartoony, and performs better than PUBG; this attracts the young youtube/twitch/etc crowd. Viral success happens.