Helldusk Armour is a legendary heavy Armour that can be worn even without any proficiency. It also grants Fire resistance and reduces damage by 3 from all sources. Lastly, it also grants the Fly spell.
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Carixim, soul-stuffed forgemaster of hellish Avernus, hammers away ceaselessly at new creations. Questions of morality and destiny do not concern him. Conscience is for his betters. He works with cheer, his swollen skin moaning soothingly.
This item does not have a Proficiency Group (in order for all classes to be 'proficient' with it). As a result, items such as Bracers of Defence, Bonespike Boots, and Corellon's Grace that are not supposed to give their bonuses while wearing armour still provide their benefits with the Helldusk Armour equipped. The extra movement speed granted to monks by Unarmoured Movement is also not lost when wearing this armour.
The Defence fighting style can grant up to +2 AC when used with this armour. For the same reason as above, Defence does not normally work with the Helldusk Armour as it is not properly considered armour. To work around this, the armour has a hidden passive that grants +1 AC if the wearer has Defence. But if the wearer also has another piece of armour equipped (e.g. a helmet), the normal +1 AC from Defence will also be applied for a total of +2 AC.