In Diablo IV, the Cold Blood quest kicks off once you complete Wrack & Ruin and open the door leading into The Slithering Dark. This area is packed with various enemies, including Nangari Spitters, Plague Swarms, Plagued Creepers, Serpent Cultists, and Elite Nangari Longfangs. As you make your way through this treacherous land, be prepared for a Diablo IV Items series of twists and turns, both figuratively and literally.
Your first major challenge occurs in the Serpentine Passage, where you’ll encounter a series of splits. To progress, take the northwest path at the first split, and then the southeast path at the second. As you proceed, you’ll eventually find a Healing Well, which provides a much-needed chance to restore health and stock up on Health Potions—essential preparation before a tough boss fight.
Once you're ready, head north, and you’ll find the Incense Box that Timue sent you to find. However, when you interact with the box, you’ll be stunned for a brief moment, and Mohlon, the Snake Queen, will emerge from the ground beside you, signaling the start of the boss fight.
Boss Fight: Mohlon, Snake Queen
Mohlon is a formidable opponent, and this fight requires quick reflexes and careful positioning. One of the first threats you'll face are the piles of Hatching Eggs scattered across the room. These eggs will explode if you linger on them for too long, causing significant damage. While you can destroy them, it’s often easier to step on and off them twice to trigger the explosions without taking damage yourself.
Unlike many bosses, Mohlon can't be easily defeated by staying behind her. You'll need to watch her telegraphed moves closely to avoid taking damage. She has a few key attacks:
Poison Stream: Mohlon will rear her head back and then spit a stream of poison in front of her. Be sure to stay out of the poison's path.
Tail Swipe: Mohlon will stretch her tail out briefly before swiping it in a wide arc. This attack deals damage and knocks you back, so keep your distance.
Eyeball Barrage: Perhaps the most dangerous attack, Mohlon summons an eyeball in her right hand, and five additional eyeballs begin to revolve around her. After a few seconds, the eyeballs shoot out around her and land on the ground. Each eyeball will track you, and if it hits you, it will shoot a petrifying light that stuns you, allowing Mohlon to land some free hits. The key to avoiding this is to keep moving and make it harder for the eyeballs to lock onto you.
At around 75% and 25% of her health, Mohlon spawns a Nangari Longfang, adding another layer of challenge to the encounter. Defeat the Longfangs, and once Mohlon falls, you can loot the Incense Box.
Completing the Quest
After defeating Mohlon, you’ll return to Yngovani by using the rope to the right of the Incense Box. Lorath and Neyrelle will be waiting for you at the top, where they’ll inform you that the incense needs to be used in a ritual at a nearby altar. Once you complete the ritual, the quest will end.
Cold Blood Rewards
Upon completing the Cold Blood quest, you will receive a substantial amount of experience and gold, with rewards scaling to your character's level. At Level 39, you can expect to D4 materials for sale receive 28,992 XP and 2,800 Gold. In addition, you’ll be granted Mohlon’s Fang, a unique dagger with potentially powerful stats. This completes the quest, and the next chapter, Judgement of the Swamp, will unlock, continuing your journey in Diablo IV.
