The ghostly reaver outfit can be made with 1,500 ghostweave which could be obtained from Treasure Hunter between 25 October 2017 0:00 UTC to 30 October 2017 23:59 UTC. This outfit cannot be stored in a Player-owned house, but can be destroyed and re-obtained through Iffie in Varrock, Diango in Draynor Village, or Ianto in Prifddinas by the holiday portal.
The outfit is composed of:
Ghostly reaver cowl
Ghostly reaver garb top
Ghostly reaver garb bottoms- Ghostly reaver boots
- Ghostly reaver grasps
