In Lost Ark Rohendel, most of the continent is woodland, inhabited by creatures such as faeries, elementals, and treants, so Rohendel is essentially the land of the elves. But many of these creatures have come under the influence of demons that you need fifteen of them to complete your Adventurer's Tome. These monsters are spread far and wide across all of Rohendel's five main competitive areas. Keep reading the contents below to find details of all the monster locations.
Go to the Fairy Settlement Triport and leave it southwest along the pathway. At the end of the path, go left of the large rock in front of you, then keep walking southwest. You will meet with a pack of Sakuul- one of which should be the Sakuul Alpha you're looking for.
You can start from the Fairy Settlement Triport, go under the archway just to your southwest and follow the path. When you walk to a large rock, turn right and follow the map's northern edge. You will face the path forks and move right to arrive at a shallow lake. There will be a large group of mobs, and the Enhanced Elemental Dust Moth you are looking for will be in the middle.
To find the monsters, you should go to the Flowstream Village first and head north, through the village, and up either of the slopes that lead up and north to the Sanctum of Water. When you arrive, you will find some Dewdrop Elemental Bosses, the closest one to your west, while you enter the sancrum proper.
Head to the Flowstream Village Triport below the village. Follow the trail to the west until you face a large shallow lake. There will be a Fierce Toadling spawn on the north side of the massive central pink lily. If you don't find it here, you can instead head directly north from here, hugging the eastern edge of the area. Keep in mind that do not go north to the Sanctum of Water.
Stand up the Foehn Plains Triport, heading east. There is a path leading south to the small market area, and do not take the path. Keep heading east, hugging the southern border along the trees. You will come across an Enraged Treant soon.
Start from the Breezesome Brae Triport and into the Verdure Plains. You will soon find the Wing Elemental Boss at the northern end of the area.
It is easy to find. Head to Flower Tree Farm. Several Furious Fire Elementals are spawning here, and you will find one you need.
Head west from the contaminated village Triport. Keep east of the path, and you will find a lead Mutated Xeneelan Beast.
Starting at the Moonkeep Hill Triport, head directly southwest down the steps, past the guards while hugging the map's right (northwest) edge. You will find Enraged Xeneela Construct in a nook on your right as you go, almost opposite the point where you can climb down towards the Celestial Plaza.
Dryad Boss is close to the Mossrock Construct Boss. When you find Mossrock Construct Boss, you only need to walk into the next nook on the south side of the path, where you can find a Dryad Boss.
You need to enter the East stardust forest. As you enter it, turn left and walk across the area into its southwestern corner to find a Corrupt Phantom Demon Dog.
Go south from East Stardust Forest Triport, then southwest at the first fork into Elzowin's Embrace. Once you arrive, stick left along its eastern edge and walk your way south. You should encounter a Wand Gargoyle Boss in the south-eastern corner.