Note: You must have level 25 minimum and be in SURVIVOR mode.

Go see the NPC named Whimsical sorcerer located in a house near the temple of Lighthaven, He will offer you to make a scroll.

Say work and it will ask you for 2 Kraanian eggs, a pink tree leaf, a flask of goblin blood and a virgin parchment.

Once these objects in your possession said to him: Reward and you will get the Silversky scroll.