Why are Bac and Ohm Runes the secret to craft the strongest Mythics in Diablo 4 Season 12? Master the ultimate farming guide!
Category: Diablo 4 Posted: Mar 24, 2026 Views: 23
While you might currently be looking forward to the second Diablo 4 expansion, which set to launch in a month, the first expansion, Vessel of Hatred, introduced many new mechanics that remain highly valuable and relevant today.
Chief among these are the rune and Runeword systems. By socketing these into your weapons and armor, you can gain exclusive buffs and benefits that are simply unobtainable through any other game mechanic!
However, the amount of gear you can equip and the number of runes or Runewords you can socket into that gear is limited. Consequently, you might be unsure which runes are the most worthwhile choices for Season 12.
With this in mind, we will focus this guide on recommending Bac and Ohm runes, detailing their specific effects and explaining how to farm them.

Rune system overview
This feature was introduced alongside the launch of Vessel of Hatred DLC and Season 6; therefore, if you wish to utilize runes today, you must first own this DLC.
All runes fall into one of three rarity tiers and belong to one of two categories: Runes of Ritual or Runes of Invocation. The former features a yellow icon, while the latter features a purple one; combining one of each type allows you to form a Runeword.
It is important to note that individual runes are inert on their own; they only become active and trigger their synergistic effects when combined in pairs and socketed into a piece of gear that possesses two sockets.
In essence, runes only become functional once they have been assembled into a Runeword.
More specifically, a Rune of Ritual generates offerings during combat. These offerings serve to empower the corresponding Rune of Invocation and trigger the combined effect of the Runewords. Your objective is simply to fulfill the specific requirements needed to generate these offerings.
What is Bac rune?
In Diablo 4, Bac rune is classified as a yellow Rune of Ritual. It generates 50 offerings, and its activation condition requires you to move a distance of 5 meters from your current location.
The most common application for this rune is to pair it with a Rune of Invocation, such as Ohm or Vex, to leverage their combined synergy and significantly boost your character's mobility.
Additionally, Diablo 4 Bac rune is one of the essential crafting materials required to create Mythic item known as Shroud of False Death.
How to craft Shroud of False Death?
Once you have unlocked Torment I difficulty or higher, you can acquire Mythic items by farming lair bosses or participating in other endgame events within the game; however, the specific rewards obtained through these methods are entirely random.
Therefore, if you wish to specifically obtain Shroud of False Death, crafting is your best option. To do so, you will need to gather the following materials:
- 2 Resplendent Sparks
- 6 Bac runes
- 6 Kry runes
- 6 Moni runes
We will cover the general methods for acquiring runes shortly; however, since Resplendent Spark is a rare item, its primary acquisition methods are as follows:
- Salvaging unwanted or duplicate Mythic items
- Progressing through Seasonal Journey and Reputation tracks to earn rewards
- Defeating Echo of Lilith (drops one upon defeat - one time only)
What is Ohm rune?
As a rune designed exclusively for Barbarian players, Diablo 4 Ohm rune requires its paired Rune of Ritual to provide 600 offerings to activate; it has a cooldown of two seconds.
The rune's sole bonus effect is to evoke Barbarian's War Cry, thereby boosting your damage output by 15% for 6 seconds.
Much like Bac rune, Ohm rune is also one of the materials required to craft Mythic Ring of Starless Skies:
- 2 Resplendent Sparks
- 6 Ohm runes
- 6 Tzic runes
- 6 Cem runes
It is worth noting that the crafting recipe for all Mythic items follows this same pattern: 2 Resplendent Sparks, plus six runes each of legendary, rare, and magic rarity.
How to farm runes?
Broadly speaking, there are two methods for obtaining runes in Diablo 4: farming and crafting. Neither method allows you to specifically target and acquire a particular rune; however, crafting does allow you to influence the rarity of the rune you ultimately receive.
Clearing Kurast Undercity
This dungeon was added to the game via VoH expansion. To unlock it, you must first complete the campaign quest Reunion within this DLC and ensure your character has reached at least level 15.
Afterward, a new quest chain titled The Kurast Undercity will guide you through the dungeon step-by-step until you are fully familiar with the area.
The unique feature of Kurast Undercity is its time-limited mechanic: you must defeat enemies within a specific time limit. However, defeating higher-level Afflicted Monsters will restore a greater amount of your remaining event time.
Defeating enemies does not grant immediate rewards; instead, you earn Attunement Points. Once the dungeon run concludes, your final rewards will be calculated based on the total points you accumulated.
Additionally, you may encounter special beacons within the dungeon. Activating these beacons triggers optional events for you to complete, providing you with extra Attunement Points and combat buffs.
If you wish to engage in more targeted farming within Kurast Undercity, you can first collect Tributes by completing other world events. Submitting these Tributes prior to your run will grant you specific bonuses based on the type of Tribute submitted.
Among these, Tribute of Harmony is the one relevant to runes. If you submit this Tribute before clearing Kurast Undercity, the total number of runes you obtain at the end will be doubled.
Defeating lair bosses
Theoretically, all lair bosses in Season 12 have a chance to drop runes; however, the highest rarity boss Belial is undoubtedly the best choice for farming.
Regardless of which boss you ultimately decide to farm, you must first acquire the corresponding lair keys. These keys are required to unlock the boss's hoard after it has been defeated, allowing you to claim all the rewards contained within, including runes.
Crafting at Jeweler
Jeweler is a vendor in Diablo 4 that allows you to perform various crafting operations. To craft a new, randomized rune, you must consume three unused runes of the same rarity, along with 4,000 gold.
The type of rune produced is independent of the specific runes used as materials; however, the rarity of the resulting rune is directly determined by the materials used. The resulting probabilities are as follows:
- Three magic runes: 85% chance for 1 magic rune; 15% chance for 1 rare rune.
- Three rare runes: 85% chance for 1 rare rune; 15% chance for 1 legendary rune.
- Three legendary runes: 100% chance for 1 legendary rune.
That wraps up everything we have to share with you this time. Although Bac and Ohm are highly sought-after, as long as you combine them effectively, acquiring other runes can be just as rewarding!
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