Once Old Scratch reaches level 34, you will be able to promote him to his latest tier (so far). He tells you of a disturbance in the Spirit World and he needs to talk to Vadima. Vadima tells you that you will need to confront the disturbance, and the only way you can do it, is to access the spirit world.
The Doom Shards in the Avernus Skyway will allow you to gain access to the Spirit World
Raven Eyes tells you that to access it, you must be Alive and Dead at the same time. The Mother Spider will be able to help you with this.
Mother Spider gives you her venom, that will not kill you, but will allow you to travel back and forth through the Spirit World
Once you enter the Spirit World, Old Scratch's old master, Dark Crawler confronts Old Scratch and you must defeat him to put an end to the disturbance in the spirit world. After you defeat him, Sister Snake congratulates you.
