In order to really push that prize pool past the current world record for esports at $10,931,103; Valve has released The International 2015 Collector’s Cache which is a collection of community made content in a chest that will contain sets for heroes. They will be different from the Immortal set as they won’t have custom animations or changes and will only be aesthetic. As an added bonus, you can also receive the Faceless Rex courier as well as Compendium levels according to the Dota 2 blog post. You gain 2 for opening 1 of these caches, 5 levels for 5 cache and 11 levels for 11 cache.
The currently available sets in the cache are the Fires of Vashundol for Doom, Armor of the Unyielding Mask for Juggernaut, Serpent of the Emerald Sea for Medusa, Flowing Entropy for Spectre, Echoes of the Eyrie for Vengeful Spirit, Brawler of the Glacier Sea for Tuskar, Knight of the Burning Scale for Dragon Knight, Garb of the Cunning Augur for Rubick, Apostle of Decay for Necrolyte, Flowersong Tempest for Windrunner and Beacon of Cerulian Light for Skywrath Mage. The Medusa set will have a custom cursor pack and the Dragon Knight set will have an extra HUD. Again when you unlock these cache’s there’s a chance that you can also obtain extra compendium points.
It’s worth noting that you can’t receive duplicates, so never fear! Go out and get that cute Windrunner set or fantastic looking Tusk set! The cache can be purchased in the Dota 2 store for $2 USD each meaning the full set will be roughly $22. It is also worth noting, these sets are exclusive to Compendium owners and will be sold up until the end of The International.