Skillbook Water + Skillbook Necromancy
Blank Skillbook Necromancy + Rain of Blood Scroll
Can be found in Fort Joy on Orivand's desk. You can enter Fort joy with Gloves of Teleportation by teleporting onto the ledge of fort joy and kicking down the ladder near Mona's Hut. In order to open the Gate, you will have to obtain the Migster's key that can be obtained from Magister Yarrow during The Murderous Gheist quest. To get into Orivand's Chambers you will need a key which can be obtained by killing Orivand himself.