To help Glissa, you need to go to the Shadow realm which is located in Prifddinas, but in another realm. You have to follow Glissa and Sarixs there. To go there, you need to give them 1 Law, 1 death, 3 airs and 1 soul rune (for each trip). But before you go there, you need to make a holy ankh. The ankh is made by using a holy symbol with a life potion (you will get this on from Sarixs), and casting a holy spell on it consuming 82 prayer points. After creating the ankh, you can finally go to the shadow realm. (Be sure to have your armour and the rest of the required runes with you, as well as a lot of food). You will stand in front of the main gate of Prifddinas, but everything is dark, and the crystals are black as well is your prayer drained. If you try to drink a prayer potion, you praye