Valve has changed how cosmetic items work in Dota 2 following the release of the third act of the "Crownfall" event. Arcana skins now have a separate slot called "Hero Base," allowing them to be combined with other customization items. Currently, this feature is available only for Pudge and Juggernaut, but it is expected to be extended to other premium skins in the future.
Source: Vikram Reddy's account on X
The new slot for Arcana allows all visual effects of the item to be retained without occupying the usual slot, enabling players to combine different skins with Arcana's effects.
On July 10, 2024, the third act of "Crownfall," titled "Icewrack Frost," started in Dota 2. The update includes a new comic, a treasure chest, and the mini-game Sleet Fighter.