There are dozens of different stats, substats, and modifiers in Diablo 4. Thorns is one such substat in Diablo 4, and while its effects are subtle, it also provides entirely automatic, essentially free damage that can come in clutch during your early-game grinding. Here’s how Thorns works.
Explaining What Thorns Is and Does in Diablo 4
Thorns is a substat in Diablo 4 that provides a benefit adjacent to the four core stats. When you have an amount of Thorns from your equipment, any time an enemy hits you, they’ll automatically take damage based on the Thorns value you currently possess.
Thorns is also passive damage — it takes no input from you to activate. As long as you’re taking direct damage from an enemy attack, it will go off. Bear in mind that damage over time will not cause Thorns to activate, so if you’re standing in an acid pool, get poisoned, or otherwise, don’t expect to be doing anything of value to the enemies nearby.
As far as damage potential is concerned, Thorns is affected by the Skill damage modifier from your Intelligence, so if you want to maximize how much damage Thorns does, that’s the stat you’ll need to pump. If you’re already playing a Sorcerer or a Necromancer (and let’s be honest, you really should be), then you’re in luck. Intelligence is your main stat.
In other words, Thorns is best used on those classes, as you’re already prioritizing the stat that boosts the ability. For the other three classes, Intelligence is still a good stat to have some points in, as the higher it is, the higher your Skill damage is — that is, the damage from every ability any class uses, on cooldown or off.
These traits make Thorns a great skill for leveling in Diablo 4 or classes and builds where you’re constantly surrounded by enemies. Sure, it’s not the best passive out there, with raw damage, cooldown reduction, and other ability uptime bonuses providing higher value, but in the absence of other buffs, having a few points in Thorns can add a little extra spice to your setup.