Thorns Damage is considered to be one of the more passive ways to deal damage to enemies but once you get the numbers up, you can pretty much charge into a group of enemies.
To make things even better, you can use the Needleflare Aspect to deal even more damage as it triggers when enemies are hit by your Thorns Damage.
This Aspect causes your Thorns Damage to not only hurt enemies that are attacking you but also those who are near you.

Needleflare Aspect Effects (Thorns Aspect)
Once you have any type of Thorns Damage going on, the Needleflare Aspect can come into play and will be triggered when enemies hurt you.
Needleflare Aspect causes a certain percentage of your Thorns Damage to hurt enemies around you, allowing you to deal more damage when you are taking hits.
This is great for those who love to dive into a group of enemies and take the fight from there, which will most likely cause you to get hit, thus causing a lot of Thorns Damage.
Needleflare Aspect Location
Needleflare Aspect can be unlocked by completing the Yshari Sanctum Dungeon, which can be found in Caldeum near the Imperial Library Waypoint. (Kehjistan)
How To Get Needleflare Aspect? (Yshari Sanctum Walkthrough)
1) Slay all enemies in the Occult Forums
Entering the Yshari Sanctum will bring you into the Occult Forums, where there will be enemies around the area that need to be cleared out for you to proceed.
2) Travel to Hell’s Annex
Once you have cleared out all of the enemies, you will need to continue exploring the dungeon until you reach Hell’s Annex.
3) Slay Emerus and collect the Key of Yshari
An enemy named Emerus will be in Hell’s Annex and you will need to find and kill him to get the Yshari Key to open up a sealed passage later.
4) Use the Key to open the Sealed Passage
After defeating Emerus, grab his key and make your way to the sealed passage so that you can unlock it and face the dungeon’s boss.
5) Defeat the Mother’s Judgement
Once you head through the passage, you will reach the Arcane Vault and will need to kill an enemy called Mother’s Judgement.
Verdict
Thorns Damage is great if you can take a hit and most tanky characters such as the Barbarian and Druid will have a lot of fun using this.
This does not mean that other classes can’t enjoy it though as some builds allow you to face enemies up close, making the Needleflare Aspect useful.
The more enemies that are attacking you, the more damage that goes around and this is a great way for taking out multiple enemies at the same time.

