The damsel of decay mission has a circular dot towards the end of the mission that you have to manage on each character.
Withering Physicality XIII - must be cured on every character or you will get one shot very easily.
Withering Faith XIII - must be cured off all priests/healers
Withering Limbs XIII - must be cured on off all DPS both caster/melee
Cure gift of death dot through out the event with a cure corruption spell
Do not cast any corruption/disease spells on the named as it will heal her.
stack goo's and bokon's on each other to get them to despawn.
I recommend not using group cures, as this will circulate the dots on all the characters. You will always have 1 of the 3 Withering dots on you when the event gets to that point. This should be around 30'ish %. That's the time to burn her down.
I used the two potions below to handle the major cures on my characters automatically. This is an example of curing a DPS/Tank. The two potions share different cool down times.
Rich (BB code):
holyshit0=/if (${Melee.Combat} && ${Me.Buff[Withering Physicality XIII].ID}) /casting "Elixir of Ethercleansing" item
holyshit1=/if (${Melee.Combat} && ${Me.Buff[Withering Limbs XIII].ID}) /casting "Distillate of Immunization XVII" item
For priest classes you would want to cure Withering Physicality XIII & Withering Faith XIII. IE: priests always want Withering limbs dot on them.
Hope that helps. Other than that it's just a lot of pain of getting to her when she warps between the platforms