Dragonsblood Spear (Thunderhead Keep skill)
Hurl the dragonsblood spear at your target, piercing all enemies along its path. Branded targets take increased damage and are aflicted with bleeding and vulnerability.
— In-game description [?]
Dragonsblood Spear is a special action skill gained by interacting with Dragonsblood Spear caches during The Crystal Blooms and The Crystal Dragon story missions. They are also available during the Thunderhead Keep meta event after [Group Event] Repair defenses and place mines! (80).