The ArmA family tree(Image credit: Future)This TikTok from Biffmatic (recently reshared by Bohemia Interactive) reminded me just how different PC gaming would look today if not for Arma, the long-running milsim series that's still going strong.Pretty much everyone knows that DayZ, one of the important PC games of the previous decade, began as an Arma 2 mod. The idea of PvPvE survival—the kind where you never know if you can trust the fella running down the road—was brand new, and it was such a hit that Arma developer Bohemia teamed up with DayZ creator Dean Hall to make a standalone version. DayZ went on to inspire a vibrant survival genre that's also given us Rust, Ark, and countless others.Did you also know that PUBG—and the entire battle royale genre, for that matter—is another Arma offspring? Brendan "PlayerUnknown" Greene developed the first version of PUBG as a mod to Dean Hall's DayZ mod. It was genuinely a mod of a mod, which Greene soon ported over to Arma 3. That mod was simply called "PlayerUnknown's Battle Royale". It was my first introduction to the mode, and remains the mode I played most in Arma 3. Greene also consulted on H1Z1: King of the Kill before joining Bluehole to create PUBG: Battlegrounds, which Epic quickly replicated within Fortnite in 2017.But did you also also know that Wardogs, the new 100-player FPS dominating Steam, is the spiritual successor to a separate Arma 3 mod? It was called Arma 3: King of the Hill, and Wardogs developer Bulkhead worked with its creators when translating the mode into the new game. The basis of three teams, one central zone, and buying gear comes straight from the Arma 3 iteration.OK, even I didn't realize that NoPixel, the gigantic GTA 5 roleplay community officially backed by Rockstar, got its start as a roleplay server within Arma 3. I remember trying a different version of Arma 3 roleplay (Altis Life) when it was new and getting repeatedly arrested by corrupt police officers for minding my own business. Judging by what I've seen of NoPixelV, it's still as goofy as those days.The legacy of Arma is astounding, and it's only possible because Bohemia has always treated its milsim like an open platform (it even runs annual modding contests, with prizes)—a grand military sandbox where genuinely innovative multiplayer ideas can find a home and eventually blossom into their own games.