Thorns is a passive effect in Diablo 4 that reflects received damage back toward enemies. When a player is hit by an enemy, the enemy will take a percentage of that damage back as Thorns damage. Thorns damage is determined by the Thorns count that can be seen in the character menu, multiplied by the respective stat. Each class scales their Thorns damage using a different stat to further multiply the damage. Thorns is primarily gained by wearing gear that has the appropriate affixes. Players can normally find random Thorns rolls on chest pieces, amulets, and pants. Shields also have a chance of dropping with Thorns, but not all classes can use these items in their off-hand slots. Some classes have skills that passively grant them more Thorns damage. Barbarians can go all-in with a full Thorns build with Challenging Shout supported by the Outburst and Tough As Nails passives. Necromancers can do the same to some extent by using the Spiked Armor passive and casting the Iron Maiden curse while using specific items that make their minions inherit a larger percentage of their Thorns damage. Thorns is most effective on high-health melee-oriented classes such as the Barbarian and Druid. On squishy characters, Thorns is less useful because it doesn’t provide mitigation.