From Diablo Wiki
Deaths Breaths are not a legendary material, though they are required in most crafting recipes, enchanting via the mystic, and higher level gem upgrading and artisan training costs. Their value increased considerably in Patch 2.3 when Kanai's Cube was added to the game, with many powerful recipes, most of which require multiple DBs.
Since Death's Breath are account bound (BoA), drop primarily from Elites, and drop at higher rates on higher difficulties, they can function as a bottleneck on crafting and other item upgrading in Reaper of Souls. Players newly arrived at level 70 (especially in a new season) often find themselves constantly out of Death's Breaths, and rationing the ones they do find between many competing potential purposes.
This shortage eases as characters gain in power and 1) stop needing to constantly spend DBs to upgrade their gear, and 2) find more DBs more quickly by killing more elites on higher difficulty levels.
Death's Breath Drop Rates
Blizzard provided the drop rates for Deaths Breaths when complaints about their infrequency were voiced shortly after the launch of Reaper of Souls. These are the chances for a DB to drop from any valid source; opening a golden chest, killing an Elite monster (yellow or blue), or killing a Treasure Goblin.
- Normal – 15%
- Hard – 18%
- Expert – 21%
- Master – 25%
- Torment 1 – 31%
- Torment 2 – 37%
- Torment 3 – 44%
- Torment 4 – 53%
- Torment 5 – 64%
- Torment 6 – 77%
Patch 2.(Reaper of Souls only) 3 added four higher levels of Torment, with increased DB drop rates. (Figures are approximate, pending Blizzard releasing official data.)
- Torment 7 – 90%
- Torment 8 – 100%, 5% chance of a 2nd DB.
- Torment 9 – 100%, 15% chance of a 2nd DB.
- Torment 10 – 100%, 25% chance of a 2nd DB.
Prior to Patch 2.3, Death's Breath were only found above level 61. Below that level there were different versions of all materials, and players found Demonic Essence instead of Death's Breath. Patch 2.3 streamlined the crafting materials, and all existing Demonic Essence were transformed into DBs.
Death's Breath drop in the Westmarch Commons.