This guide shows the location of all 9 Deathroots in Elden Ring. You can feed Deathroot to Gurranq in the Bestial Sanctum and you will get some items in return. You can easily reach Bestial Sanctum by following D’s questline.
Deathroot 1/9: Defeat Tibia Mariner in Limgrave
Defeat the Tibia Mariner miniboss in the Summonwater Village and he will drop a Deathroot. Feed it to Gurranq and you will get Clawmark Seal and Beast Eye.
Deathroot 2/9: Black Knife Catacombs
You will get this Deathroot inside a chest in the boss lair in the Black Knife Catacombs. Feed it to Gurranq and you will get Bestial Sling.
Deathroot 3/9: Deathtouched Catacombs
You will get this Deathroot inside a chest in the boss lair in the Deathtouched Catacombs. Feed it to Gurranq and you will get Bestial Vitality. Deathtouched Catacombs is on the north portion of Limgrave. The entrance of the cave is marked in the pictures below. To reach the cave entrance, take the path west from the Saintsbridge Site of Grace. Then jump on the rocks to climb up and reach the dungeon entrance. The path to reach the entrance is marked with a red arrow in the picture below.
Deathroot 4/9: Defeat Tibia Mariner in Liurnia
This one is dropped by Tibia Mariner in Liurnia at the location marked in the picture below. Feed it to Gurranq and you will get Ash of War: Beast’s Roar. When you visit Gurranq again, he will be hostile to you. Lower down his HP and make sure that you don’t kill him. When he kneels, talk to him and exhaust all the dialogue options.
Deathroot 5/9: Defeat Tibia Mariner in Altus Plateau
This one is dropped by Tibia Mariner in the Wyndham ruins in Altus Plateau at the location marked in the pictures below. Feed it to Gurranq and you will get Beast Claw. To reach Wyndham ruins, go uphill towards north from the Erdtree glazing Hill Site of Grace and turn left as shown by the red line in the second picture below.
Deathroot 6/9: Gelmir Hero’s Grave
You will get this Deathroot inside a chest in the boss lair in Gelmir Hero’s Grave. Feed it to Gurranq and you will get Stone of Gurranq.
Deathroot 7/9: Defeat Tibia Mariner in Mountaintops of the Giants
This one is dropped by Tibia Mariner in Mountaintops of the Giants at the location marked in the picture below. Go north from the Snow Valley Ruins Overlook Site of Grace and drop down to reach the Tibia Mariner’s location. Feed it to Gurranq and you will get Beastclaw Greathammer.
Deathroot 8/9: Giants Mountaintop Catacombs
You will get this Deathroot inside a chest in the boss lair in the Giants Mountaintop Catacombs. Feed it to Gurranq and you will get Gurranq’s Beast Claw.
Deathroot 9/9: Hidden Path to the Haligtree
Go to the Hidden Path to the Haligtree. You will need Haligtree Secret medallions to unlock this area.
From the Hidden Path to the Haligtree Site of Grace, go down the stairs and then turn left. Keep moving ahead until you reach the central platform. From the central platform, jump down from the location shown in the picture below. You will land on an invisible bridge.
On the invisible bride, walk down in the north direction as shown below.
At the end of the path, turn left and go in the west direction. At the end of the path, jump down on the ground below as shown in the picture below. Here you can climb up the window to enter the building. Inside the building, you will find a lever on the right side. Pull the lever to open the Boss Door. Then turn around and go straight ahead to reach the boss lair. Defeat the Stray Mimic Tear boss inside. Then open the chest to get the final Deathroot. Feed it to Gurranq and you will get Ancient Dragon Smithing Stone.
This completes the questline. But after this, Gurranq will appear again towards the end of the game in the Crumbling Farum Azula. You will have to fight him during the first phase of Maliketh, The Black Blade. This is not an optional boss and is unmissable. If you have given all the 9 Deathroots to Gurransq, then you will get a few extra dialogues here.