Diehard Team Fortress 2 fans have spent all weekend sleuthing out Friday's tease, in which a "Gray Mann" is revealed to be the brother of Redmond and Blutarch Mann, owners of the game's RED and BLU teams. Tons of evidence suggest this is going to mean the introduction of a robot faction, which Valve itself all but confirmed today in two more clue dumps—the will of the brothers' father and, more importantly, a new webcomic in which Gray is shown for the first time.
Read it for yourself, but it's quite apparent this guy Gray uses some heavy duty prosthetics. The will, which surfaced sometime overnight, can be found by clicking on a second bloodstain appearing on the banner of the Team Fortress 2 homepage.
A NeoGAF reader also notes that, on the front page logo, Scout, Heavy and Spy all seem to be giving Engineer dirty looks, which conforms to the thesis of that amazing video at left. It collects two years' worth of visual clues, leaks and curiosities that imply Engineer is responsible for the construction of a robot team, and that whatever this mode of play is to be, it'll be called "Man vs. Machine."
Sure, maybe we kinda know what this is all about by now, but that doesn't mean a forensic investigation of it isn't fun. Especially if it reveals some kind of a canonical structure for this feature going back two years. For more, visit the thread on NeoGAF, they seem to have uncovered some kind of encrypted file in the latest update, which upon decoding looks like the basis for another ARG.
Update: Reader iamjethro explains both the ARG and how the webcomic was discovered.
Someone found out by equipping an item that was not supposed to be equippable and high fiving someone, the person you high fived would receive a secret message in the form of a joke. The jokes turned out to be hidden hex code, which then revealed nine things. Eight of them just revealed a word, but the nineth one revealed a zip with a password lock (a Keepass thing). Using the words as a PDP code list somethignsomthingsomething(I'm not exactly sure here), people found a link inside linking to tf2.com which turned out to be a crafting recipe in game. Crafting all the items together caused a GAME wide message, linking the comic.
And that my friends, is a VALVE ARG. Special thanks given to the fine people who inhabit the valvearg.com chat for solving all this.