Runes have become one of the most important endgame resources in Diablo 4 Season 15. With the return of classic-style Runewords, players now have a reason to keep everything from low-tier Tir and Eth Runes to expensive Ber and Jah Runes.

The important part is understanding that not every Rune can be upgraded into the next tier. Season 15 has two separate upgrade paths, so efficient farming means knowing when to save, when to transmute, and when to stop spending materials.

Where to Farm Runes

Several Season 15 activities can provide Runes, but the best choice depends on your current character strength.

Kurast Undercity is a strong option when you want to combine Rune farming with experience and general progression. The right Tribute can make Rune rewards a major part of the run.

Waking Nightmares are another useful source, especially when you want Runes alongside other seasonal rewards.

For high-end farming, Worldstone Keep and Baal Runs are attractive because you can combine Rune hunting with powerful gear, Mythic Unique opportunities, and other Season 15 rewards.

If you are still building your character, do not force high-level content simply because it can drop better Runes. A faster lower-tier farming route can produce more useful resources per hour.

Your Diablo 4 Items should therefore be strong enough to clear your chosen activity quickly and consistently before you move into higher difficulties.

The Low-Rune Upgrade Path

The first Rune ladder starts with Tir:

• 3 Tir → 1 Eth
• 3 Eth → 1 Ith
• 3 Ith → 1 Tal
• 3 Tal → 1 Ral
• 3 Ral → 1 Ort
• 3 Ort → 1 Thul
• 3 Thul + Chipped Topaz → 1 Amn
• 3 Amn + Chipped Amethyst → 1 Sol

This path is useful when you have large quantities of low Runes that are not needed for your current Runewords.

However, there is an important limitation.

Sol cannot be upgraded into Mal.

The high-Rune ladder starts separately at Mal, so you cannot simply collect thousands of Tir Runes and convert them all the way into Jah.

The High-Rune Ladder

Once you have access to the required high-tier Runes, the Cube becomes much more valuable.

The current recipes are:

• 2 Mal + Flawless Amethyst → 1 Ist
• 2 Ist + Flawless Ruby → 1 Vex
• 2 Vex + Flawless Emerald → 1 Ohm
• 2 Ohm + Flawless Diamond → 1 Lo
• 2 Lo + Grand Topaz → 1 Ber
• 2 Ber + Grand Sapphire → 1 Jah

This is the most important part of the system for players chasing expensive Runewords.

For example, if your target is Ber, two Lo Runes plus a Grand Topaz give you a guaranteed Ber instead of relying entirely on a direct drop.

Ber and Jah Farming Strategy

Ber should usually be treated as a major milestone rather than a Rune you immediately convert.

Enigma requires Jah + Ith + Ber, while Infinity requires Ber + Mal + Ber + Ist. Because Ber is used in multiple expensive Runewords, spending your first Ber without planning can slow down your progression.

Jah is even more expensive to create because it requires two Ber Runes and a Grand Sapphire.

If Enigma is your primary goal, keep the Ber required for the craft before considering a Ber-to-Jah conversion.

Cube Upgrades: When Are They Worth It?

The Cube is most valuable when you have duplicate Runes that are not immediately needed.

For low Runes, upgrading can be convenient because the required materials are relatively easy to obtain. For high Runes, however, every conversion represents a significant investment.

Do not upgrade automatically just because the recipe is available.

If you need one Ber for a specific Runeword, converting two Ber into Jah may actually delay your final craft. Always work backward from the Runeword you want to build.

Best Farming Rotation

A practical Season 15 Rune routine is:

• Early progression: Waking Nightmares and Undercity.
• Mid-game: Focus on Rune-producing activities while improving your character.
• Endgame: Add Worldstone Keep and Baal Runs to your farming rotation.
• High-Rune stage: Save Mal, Ist, Vex, Ohm and Lo instead of blindly converting everything.
• Final stage: Use the Cube to create Ber and Jah when the required materials are available.

Season 15 Rune farming rewards planning more than simply collecting every Rune that drops. Low Runes can be converted through the first ladder, while the high-tier progression begins at Mal and eventually leads to Ber and Jah.

The biggest mistake is treating every Rune as interchangeable. Keep track of the Runewords you actually want, reserve expensive Runes for those crafts, and only use the Cube when the conversion moves you closer to your target.

If you are preparing a new Runeword build and considering whether to buy Diablo IV Items, remember that Rune farming is still one of the most reliable ways to progress naturally. With a fast farming build, efficient activity rotation, and careful Cube management, even Ber and Jah become realistic long-term goals rather than purely lucky drops.