U4GM Guide to Ber Rune Uses in Diablo 4

To unlock the Cabochon Merchant in Diablo 4, select Gutter Filth and Bauble Day in the Undercity War Plans tree, defeat a Portal Prankster during your run, then kill the District Boss. Planning your D4 Gold spending starts with getting that encounter to appear. In Season 15, the merchant can stock Ber runes, crafting gems, and socketable splinters, so this setup gives you a shopping stop at the end of a successful run.

Which Diablo 4 War Plans nodes unlock the merchant

You need Gutter Filth on the left of the Undercity tree and Bauble Day in the middle. Gutter Filth gives beacon activations a chance to summon a Portal Prankster, while Bauble Day makes defeating that enemy trigger the merchant encounter after the boss. Select both before entering, because each handles a different part of the unlock.

The practical difference is where you put your attention during the run. Beacons now serve two purposes: building attunement and giving you another opportunity to summon the enemy you need. Reaching maximum attunement doesn't complete the merchant requirement, so check remaining beacons when you haven't defeated a Portal Prankster.

How do you trigger the Diablo 4 Cabochon Merchant encounter

Defeat one Portal Prankster, finish the dungeon, and look behind or beside the reward chests after the District Boss falls. Watch for its goblin-style map marker while activating beacons, then take it down when it appears. The message about treasure in the boss lair confirms that you've completed the enemy requirement for that run.

You don't need a Tribute or an Undercity sigil specifically for this encounter. One defeated Portal Prankster is enough, so you can focus on finishing once that condition is met. Its appearance is random; treat a run without one as another attempt, rather than assuming that maximum attunement should have unlocked the shop.

How do Cabochon Merchant purchases and refreshes work

Purchases use gold, while each paid inventory refresh costs 666 Forgotten Souls. You can buy items and refresh stock during the same merchant encounter, which means another dungeon clear isn't required for every new selection. Check the free refresh offered in the shop before spending Souls, then decide how many paid refreshes your reserve can support.

Ber is listed at 50 million gold, but finding the merchant doesn't guarantee finding that rune. Lo, Ohm, and Vex can also move your crafting plan forward when the right ingredients are available. Set a stopping point before refreshing: 50 paid refreshes consume 33,300 Forgotten Souls, and that spending carries no promised Ber total.

Your shopping list should include the gem cost. The listed prices put Royal gems at 50 million gold and Grand gems at 500 million, with Flawless gems estimated around 5 million. A Grand Topaz bought for a Ber craft can therefore cost substantially more than a direct Ber purchase, so check your existing gem stock before committing to precursor runes.

What should you check before spending on Ber ingredients

Open the Cube and confirm the displayed Lo and Ber recipes before buying enough runes for your craft. The quantities differ between the recipe versions: Ber uses either two or three Lo with one Grand Topaz, while Lo uses either two or three Ohm with one Flawless Diamond. That difference changes how useful each merchant purchase is to your current inventory.

With both two-rune recipes, crafting one Ber entirely from Vex requires eight Vex, four Flawless Emeralds, two Flawless Diamonds, and one Grand Topaz. Those totals change when either upgrade requires three runes. Infinity needs two Ber per craft, so count your completed runes and remaining ingredients against that target before another refresh session.

Set your War Plans nodes, secure the Portal Prankster kill, and finish with a shopping list based on the Cube recipe you've checked. Once your Infinity materials are accounted for, you can buy d4 gear to fill the next gap in your build and get back to your runs.