Blizzard has hidden Diablo 2 Runewords nobody told us about in Diablo 4's Season of Hell's Legacy
Stealth, Enigma, Grief, Spirit, and more can apparently be crafted through the Horadric Cube.

Diablo 4 Season 15 finally launched after a good 4 hours of login issues, and it did not take long for players to find things Blizzard did not mention in the patch notes.
It turns out they added a collection of classic Diablo 2 Runewords that have secretly made their way into Diablo 4 as special Unique items. Someone who was streaming the season launch discovered the first one, Stealth, by combining a white armor piece with the required runes in the Horadric Cube.
wudijo@wudijo𝕏Okay Blizzard COOKED with S15, @DiEoxidE_ just made a "Stealth" while we were hanging out. Now the rest of us just need to be able log in 🤣 #DiabloIV

Instead of revealing a normal recipe, the Cube simply displays "???" before you transmute the items and discover what you have created. Very Diablo 2.
How Do Runewords Work in Diablo 4?
The system is not quite the same as it was in Diablo 2. You are not socketing Runes into an item and having the Runeword appear. In Diablo 4, you can place a compatible white item and the required Runes into the Horadric Cube.
The resulting item is a Unique based on one of Diablo 2's famous Runewords.
So far, players have found recipes for a few classics, including Stealth, Enigma, Grief, Spirit, Call to Arms, Infinity, Insight, Phoenix, Leaf, Lore, King's Grace, Ancient's Pledge, Holy Thunder, Prudence, Rain, Strength, Pattern, Edge, and Zephyr.

For example:
Stealth requires a chest armor base alongside a Tal and Eth Rune
Enigma uses Jah, Ith, and Ber
Spirit can be crafted with Tal, Thul, Ort, and Amn using a compatible weapon and off-hand
The effects have been adapted for Diablo 4, so they are not just copying the original items from Diablo 2 either.
Blizzard Did Not Mention Any of This
What is making the discovery particularly fun is that none of these Runewords appeared in Blizzard's Season 15 patch notes or the detailed Season of Hell's Legacy announcement.
The season was already full of Diablo nostalgia, including returning bosses, Legacy Uniques, and Waking Nightmares based on previous games, but Blizzard apparently decided that was not enough and left a few more surprises for us to uncover ourselves.
The exact list of available Runewords and their recipes is still being pieced together by the community, but we will share those once we have them as well.
For now, if you have got some spare Runes and a white item sitting in your stash, it might be worth experimenting with the Horadric Cube. You never know what Blizzard decided to hide in there! And maybe we can even find some more surprises related to previous games during this Season of Hell's Legacy!
