How does Thorns work?

I’m trying to figure out how thorns works so I can start deciding how to approach making a viable thorns build. Stacking some thorns on my Crusader has led me to believe that it’s not as simple as it sounded at first.

I have around 7,000 thorns right now, but when enemies attack me, they take over 90,000 damage. I’ve also seen the thorns damage crit, and I’ve also seen enemies take upwards of 2 million damage from a single activation of thorns.

With Vo’Toyias Spiker equipped and using Iron Skin with Reflective Skin and Provoke with Charged Up, I’ve just utterly melted enemies, seeing crits of over 8 million. None of my active attacks can deal even 2 million damage, so these massive numbers must be from some combination of these skills.

Is thorns return damage somehow a function of how much damage I sustain? What if I block or dodge? What is the approximate formula for damage return based on my current thorns?


After doing some math, I arrived at the following formulas for thorns damage:

Regular Attack

  • ((S / 100 / 4) + 1) * T

Reflective Skin Attack

  • ((S / 100) + 1) * 2T * (P / 100 + 1)


  • S is Strength (or mainstat)
  • T is your thorns damage
  • P is your Physical Damage bonus (as a percent)

It does not appear that regular thorns damage can crit, nor is it based off your weapon damage or the damage done to you. It did not to appear to be affected by any damage reduction modifiers nor is it improved by bonuses to Physical Damage Skills. It is scaled according to your mainstat by 1/4

Reflective Skin does indeed double your base thorns damage. However, because it is a skill doing the damage and not the thorns mechanic, it scales off your mainstat like all other skills (not at a 1/4 ratio). It is also then eligible to crit and receive your “+X% Damage to Physical Skills” bonuses. This is the reason for the (more than 2x) large spike in damage when using Reflective Skin.

An example:

For a crusader with 5000 Strength and 10000 Thorns and 20% Bonus to Physical Skills:

  • A regular attack would deal 135,000 damage.
  • An attack while Reflective Skin is active would deal 1,224,000 damage
    (with the option to crit).

Source : Link , Question Author : Invader Skoodge , Answer Author : TheCheeseGod

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