Gruelling Madness is a Debuff in Path of Exile 2 which is tied to Delirium Items.


Gruelling Madness is a stacking Debuff which first inflicts a Slow, with subsequent stacks then increasing the potency of any Slowing effects on the target.
The first stack of Gruelling Madness inflicted on a target Slows their Movement Speed by 15%. Additional stacks beyond the first will increase the potency of all Slowing Debuffs on the target by 10% per stack, and can stack up to a maximum of 10.
Gruelling Madness is a Debuff that can be inflicted when using certain Delirium-themed Unique items:
The Auspex,
The Raven's Flock and
Sadist's Mercy.
Gruelling Madness does not have a Duration, but stacks are lost at a rate of one every 2 seconds if no new stacks of Gruelling Madness are inflicted on the target.
The
Sadist's Mercy Unique Mace has the special modifier 'Enemies in your Presence have additional Power equal to their Gruelling Madness'. This modifier raises the Power of affected targets based on the number of Debuff stacks they have. For more information about Monster Power, check out our guide here!