13 new hero sets are included in Chest of Endless Days, which is a random drop for matching players. 

The Chest of Endless Days, which is comparable to the Diretide chest that Valve launched in 2020, is a random reward for players who participate in matchmaking. However, in order to open it, you must have a key that is available for $2.49 in-game.

On a social media post via Twitter – Wykrhm Reddy @wykrhm tweets

Chest of Endless Days now available — Includes a brand new skin for Kid Voker. https://dota2.com/newsentry/5148191896088229925 #Dota2

The treasure brings a new set for the young Invoker Persona which has an ultra rare drop chance. Those who don’t have the Invoker persona will automatically unlock the style upon receiving the new set.

Hoodwink is also featured in the new chest with very rare dropping odds, while Witch Doctor received a rare drop chance item set.

Chest of Endless Days – full list of item sets

• Madness of the Amaranth Orb – Luna
• Faceless Destiny – Templar Assassin
• Vespoid Stalker – Weaver
• Prolific Planter – Nature’s Prophet
• Toll of the Netherlight – Viper
• Discipline of the Dark Star – Drow Ranger
• Unholy Harvest – Wraith King
• Foxtail Libertine – Pangolier
• Polar Night – Winter Wyvern
• Requiem for Red Wolf Clan – Lycan
• Servant of the Sightless Shamans Monkey King (Rare) – Witch Doctor
• Scourge of the Skyrangers (Very Rare) – Hoodwink
• Heir of Menace (Ultra Rare) – Kid Invoker