As nasty as it may be, this trembling hand is one of the items needed to summon a powerful enemy that you may have faced in the Season of the Malignant.
This Malignant Hand is one of the items needed to summon the Echo of Varshan, who you may battle at a new location in Sanctuary.
Once you have a Trembling Hand and the other 2 ingredients required to summon the Echo of Varshan, you can fight him to get valuable loot.
How To Get Trembling Hand?
You can get a Trembling Hand in multiple ways but your best chance would be to obtain it from a Tree of Whispers Cache and this drops by a small chance starting from World Tier 3.
Aside from obtaining it from a Tree of Whispers Cache, you may obtain them rarely from tougher enemies, mainly those that spawn from a pool of blood in Blood Harvest zones.
If you already have the other parts and have enough to spare, you can use them to create Malignant Body Caches at an Alchemist for a chance to get a Trembling Hand.
Using other parts to create Malignant Body Caches will require other rare resources as well and it might be best if you just keep them for later.
Trembling Hand Uses
These are used together in the Ritual of Hatred and a Malignant Altar, which will be consumed with the other ingredients to summon the Echo of Varshan.
After the Echo of Varshan has been summoned, you will be able to battle him and upon defeating him, you will get tons of rewards.
Trembling Hands on their own won’t be of much use as you need the other items to summon the Echo of Varshan and it would be best to save it for later.
Although you can use other parts to make a Malignant Body Cache, it is better that you save them instead since you will get all the parts eventually.
You can carry multiple Trembling Hands at a time, which allows you to farm them and the other items until you are ready to face the Echo of Varshan.