This follows yesterday's Demoman update, which brought a Close Combat Kit consisting of a sword and shield with mixed effects. The haunted Eyelander sword decapitates enemies when killed and decreases the Demoman's maximum health. Meanwhile, the Chargin' Targe shield replaces the sticky bomb launcher, protects against fire (+50%) and blast (+65%) damage, and can be used as a stabbing weapon.
The War has pitted Solider and Demoman players against each other, with the winner receiving a new (undisclosed) unlockable weapon. The event will end tomorrow night, and the Soldier is currently leading the Demoman's casualty count (4,923,531 versus 5,056,134). In addition to the new exclusive weapon, tomorrow's update will bring a crafting system, new maps, achievements, "surprises" and the remaining weapon unlocks.
To celebrate, Valve has announced that Team Fortress 2 will be free to play for four days immediately after the update (Thursday through Sunday). If interested, you can preload the game now. It's also worth noting that a new TF2 comic was introduced yesterday and today.