The Bedeviled Grotto is a Malignant Tunnel that was introduced during the Season of the Malignant that players can explore.
It is mostly Serpent Cult members as well as the Nangari creatures roaming around it, which can sometimes be a deadly threat.
You will need to explore this dungeon and take out several enemies before getting rid of a Malignant Corruption at the end.
Bedeviled Grotto Location
You may find the Bedeviled Grotto in the Blackguard Bog on the Forsaken Coast, which is located within the region of Hawezar.
The fastest way for you to reach this Malignant Tunnel is to head northwest from Backwater as this is the closest Waypoint available.
Bedeviled Grotto Objectives
1) Slay all enemies in the Vile Burrow
Upon entering the Bedeviled Grotto, you will find yourself in the Vile Burrow and will have to clear all of the enemies in the area.
This can easily be done by checking your map to see where the enemies are since they will be marked on your map when you are nearby.
Once all of the enemies have been slain, you will need to search for an Elite Nangari that goes by the name Alcanthe.
2) Slay Alcanthe, Malignant Serpent
As soon as Alcanthe appears, you will need to fight the beast until it has been killed, which will cause it to drop a Malignant Heart.
You can interact with the Malignant Heart that Alcanthe has dropped to summon it again and slay it once more to get a Caged Heart. (This part is optional)
The Malignant Serpent has the following affixes:
3) Destroy the Malignant Corruption
After defeating Alcanthe, there is one more threat that needs to be taken care of and this is a single Malignant Corruption further down the tunnel.
You will need to find the Malignant Corruption and destroy it but beware, an Elite Malignant enemy will appear and attack you along with other monsters.
The Bedeviled Grotto is one of the longest Malignant Tunnels that were introduced in the game since it has 3 objectives that need to be completed.
It is best to watch out for the Nangari as they can poison and even turn you to stone while the Serpent Cultists can sometimes deal a great amount of damage.
Completing the objectives for this Malignant Tunnel will allow you to proceed to the end, where a Devious Outgrowth can be interacted with if you have a Devious Malignant Key.