The Cleanse is a Bilefen side quest seen in Diablo Immortal. It is activated by talking to Cadeus whenever he appears at Port Justinian.

Objectives
- Find the fouled pool (0/1).
(Cadeus thinks that Port Justinian's water sources might be partially fouled. Find the source and bring him a sample) - Kill the Maggot Brood (0/1).
- Retrieve the bog water sample (0/1).
- Bring the bog water sample to Cadeus.
(Bring the bog water sample to Cadeus in his hut) - Help Cadeus test the antidote (0/14).
(Cadeus is using the water sample as part of a test on himself. Help him deal with the aftereffects) - Give Cadeus the Green Vial (0/1).
(Cadeus needs to adulterate the new mixture with some of the old antidote. Bring him the green vial on his desk) - Kill the maggots (0/3).
(Cadeus is still disgorging maggots. Help him deal with the last of them) - Talk to Cadeus
Transcript

- Cadeus: Back into the wetlands? Don't... ugh... drink the water. I've seen evidence of green death: fever, nausea, dessicated skin. I think... it's spreading.
- Class: What's the cause?
- Cadeus: If I knew, maybe I could develop an antidote. I'd go get a water sample... but I'm a little under the weather. I ought to stay here in case any other sick people show up.
- Class: I can help. Let me find the source and bring you a sample.
- Cadeus: Bring it back to my cabin. If you can.
- At the fouled pool

- Class: That's it. No question.
- Collect a sample from the pool

- Class: Now I see the problem.
- After killing the Maggot Brood, deliver the sample to Cadeus in his hut

- Cadeus: Thank... you. A bit of the contaminant... should make a more... resilient antidote.
- Class: Are you okay?
- Cadeus: No. But I... might be, if this works. It's a chance to make things right.
Not... everyday I get to test a cure... on myself. Make sure you take notes.
- Give the bog water sample to Cadeus. He takes the new antidote
- Cadeus: Oh... no... I can feel them moving...
- Cadeus vomits bog larvae
- Cadeus: Uieeehh!
- Cadeus continues to vomit larvae. Protect Cadeus from the larvae until the antidote runs its course
- Cadeus: Get the green vial on the desk.
- Give Cadeus the Green antidote on the desk
- Cadeus: Made a... test batch... after Owens.[1] I... think it might interact with the antidote. A good interaction.

- After killing the larvae
- Cadeus: Even with both doses... it's like I can still feel them... crawling around in my guts. Ugh. I hope... that's the last of it.
Don't think... this antidote will work for the whole port. Maybe we can ration it... for the worst cases.
I'm not going to stop trying... I just need to rest.
If this is half of what Owens went through, it's already enough.
We can't save everyone, but we certainly can try.