Because Destiny 2's Moon is a very strange place, you can make weapons from Essence. The Essence of Rage will give you the One Small Step Shotgun, as long as you can cleanse it. To do this, you will need to find the Fangs of ShunGath. In this guide we will show you where to find them.
Destiny 2 – Fangs of ShunGath Location – World's Grave
To get to the World's End, just spawn in Eris Morn, hop on your Sparrow and head right for the Anchor of Light. Go past the first right turn that would take you down to the Fallen area, and take the second smaller turn to the right. This will bring you to the Temple of Crota. Go inside, then just continue down to the room with the encased metal platform in the center. Go to the back of the area and turn left, head down the stairs, and turn right into the next room, then out the exit that will be in front of you.
Continue along this path until you arrive at the World's Grave. When you get there, go straight through the first room, then jump onto the platform at the end and go left. This will bring you to the room that ShunGath is in.
Now, they don't want to give up their fangs, so just kill them and they will end up in your inventory. After that, finish up the rest of the Essence challenges, or return to the Lectern to collect your new weapon. You will find a video above that will show you how to get to where you need to be in the World's Grave.
ShunGath is not particularly difficult to kill, so you should have no real issue with this, no matter what Power level you are. Best of luck, Guardian!