Blood of Sargeras

Blood of Sargeras is a powerful reagent found throughout the Broken Isles. Blood of Sargeras is often used as a tempering agent by master craftsmen, and to bind magic in weapons and armor. It is red when solidified, and seems to be Sargeras' literal blood.

Source
This item can be found from:
 * Mining, gathering herbs, and skinning at 2 stars mastery on the Broken Isles
 * World quest rewards
 * Bosses in Legion dungeons on Heroic and Mythic mode

Alchemy

 * Infernal Alchemist Stone

Blacksmithing

 * Demonsteel Armguards
 * Demonsteel Boots
 * Demonsteel Breastplate
 * Demonsteel Gauntlets
 * Demonsteel Greaves
 * Demonsteel Helm
 * Demonsteel Pauldrons
 * Demonsteel Waistguard
 * Consecrated Spike
 * Flamespike
 * Gleaming Iron Spike
 * Terrorspike
 * Steelbound Harness

Enchanting

 * Leylight Brazier
 * Immaculate Fibril
 * Soul Fibril

Engineering

 * Mecha-Bond Imprint Matrix
 * "The Felic"
 * Shockinator
 * Double-Barreled Cranial Cannon
 * Ironsight Cranial Cannon
 * Sawed-Off Cranial Cannon
 * Semi-Automagic Cranial Cannon
 * Trigger

Inscription

 * Aqual Mark
 * Straszan Mark

Jewelcrafting

 * Dawnlight Band
 * Maelstrom Band
 * Prophetic Band
 * Shadowruby Band
 * Ancient Maelstrom Amulet
 * Blessed Dawnlight Medallion
 * Grim Furystone Gorget
 * Intrepid Necklace of Prophecy
 * Raging Furystone Gorget
 * Righteous Dawnlight Medallion
 * Sorcerous Shadowruby Pendant
 * Subtle Shadowruby Pendant
 * Sylvan Maelstrom Amulet
 * Tranquil Necklace of Prophecy
 * Twisted Pandemonite Choker
 * Vindictive Pandemonite Choker
 * Chatterstone

Leatherworking

 * Dreadleather Belt
 * Dreadleather Bindings
 * Dreadleather Footpads
 * Dreadleather Gloves
 * Dreadleather Jerkin
 * Dreadleather Mask
 * Dreadleather Pants
 * Dreadleather Shoulderguard
 * Gravenscale Armbands
 * Gravenscale Girdle
 * Gravenscale Hauberk
 * Gravenscale Leggings
 * Gravenscale Spaulders
 * Gravenscale Treads
 * Gravenscale Warhelm
 * Elderhorn Riding Harness

Tailoring

 * Imbued Silkweave Bracers
 * Imbued Silkweave Cinch
 * Imbued Silkweave Cover
 * Imbued Silkweave Drape
 * Imbued Silkweave Epaulets
 * Imbued Silkweave Flourish
 * Imbued Silkweave Gloves
 * Imbued Silkweave Hood
 * Imbued Silkweave Pantaloons
 * Imbued Silkweave Robe
 * Imbued Silkweave Shade
 * Imbued Silkweave Slippers

As a quest objective

 * A Taste For Blood
 * A Thirst For Blood
 * Blood of Sargeras (quest)
 * Focusing the Energies
 * Lining the Crucible
 * Tempering Darkness
 * The Price of the Black Market