Valve releases the new Dota 2 Chest of Endless Days that can be opened only with purchased keys.
Each treasure opened will grant a set for Luna, Templar Assassin, Weaver, Nature's Prophet, Viper, Drow Ranger, Wraith King, Pangolier, Winter Wyvern, or Lycan. You'll also have a chance to unwrap a Rare Witch Doctor set, Very Rare Hoodwink set, or Ultra Rare Kid Invoker set, which includes the base Kid Invoker persona if not already owned.
These treasures are not available directly for purchase. Instead, they will drop randomly to players as they compete in Matchmaking. A key is required to open this chest — purchase one to unlock the treasure for $2.49, or sell the treasure on the market.