My character who is Blade Master got the quest from Moyong Jung in Foshi Pyres. The quest is called The Source of the Bloody Jiangshi and it's about defeating Nekuro.
Accoding to Moyong Jung's story, he watched Nekuro die with his own eyes but the incantations coming from the Bloody Jiangshis were identical to those used before.
Moyong Jung also said Nekuro betrayed all of them. Nekuro stole ancient, arcane manuscripts and killed their master while their master was sleeping. Nekuro was eventually caught and was sentenced to death but Nekuro came back from the dead.
My Blade Master accepted the quest and immediately went to the Defiled Tomb to face Nekuro. In the Defiled Tomb, my Blade Master fought Tomb Revenants and Infernal Jiangshis before facing Nekuro and his guards.
Nekuro was guarded by two Nekuro's Awakened Guardians, my Blade Master fought them first before fighting Nekuro.
The Dark Shaman Nekuro started the battle by casting an Ice Magic Spell on my Blade Master but my Blade Master dodged it and relentlessly slashed Nekuro until Nekuro went down.
Defeating Nekuro completed the first objective. For the second objective, my Blade Master went back to Moyong Jung in Foshi Pyres to report what happened.
My Blade Master was rewarded with 400 Experience Points and an Ethereal Phantom outfit in Blade and Soul.