Upgrade Direct Item to Mythic - Horadric Cube recipe - Diablo IV Season 15
The Upgrade Direct Item to Mythic recipe in the Diablo IV Horadric Cube takes 1x Ancestral Unique equipment item (non-Iconic; 'Crafted'-tag-eligible) + 5x Resplendent Spark and produces Mythic-quality version of the input item.
Inputs
1x Ancestral Unique equipment item (non-Iconic; 'Crafted'-tag-eligible) - Must be Ancestral and cannot be Unmodifiable. The game files gate it on the item being an Ancestral Unique, not on an Item Power number; the Season 14 upgrade required 850. In game this recipe is named Upgrade to Mythic.
5x Resplendent Spark
Output
Mythic-quality version of the input item - 1:1 deterministic transfer - keeps ALL of the input item's existing affixes, Tempering, and Masterworking exactly as rolled. No RNG on the output.
Restrictions
Cannot be used on an Unmodifiable item
Result carries the 'Crafted' tag; only one Crafted-tag item can be equipped at a time
Iconic Mythics remain obtainable only as Mythic-quality (cannot be produced by this recipe from a Unique version, since Blizzard scrapped PTR plans for Unique versions of Iconic Mythics)
upgradeVisiblebothNew in Season 15
Blizzard quote: "will be more expensive than the recipes through the Blacksmith or Jeweler, but it will also be a total 1:1 transfer... the random factors are gone. Put in a Tibault's Will with ideal affixes and dialed-in Tempering and Masterworking, and you'll get a Mythic-ized version... with all affixes and modifications retained. The only restriction is that you cannot use this recipe on an Unmodifiable item." Jeweler/Blacksmith-crafted Mythics do NOT carry the Crafted tag, so multiple of those can be equipped simultaneously alongside one Crafted-tag item. Blacksmith also gained a second cache in S15 that rolls only Iconic Mythics at the same cost as the normal Mythic cache.