This is my interpretation of what happened after Pharaun got chewed up by an army of spiders. ENJOY!!
Pharaun woke up.
It was a strange thing, having to wake up after he had died, but it felt somewhat refreshing. He had to be in a new body, but he couldn't move. Incredibly strange, that.
His eyes twitched from side to side, getting used to this new body, which was still that of a drow, but slightly stronger than the previous one he had. His magnificent repitoire of spells still lingered in his mind, but things were hazy, and he had to work on his memory before he could do some spellcasting.
It was only then that his lungs started to burn, and Pharaun realized that he hadn't been breathing. He jolted upright, taking in that first refreshing breath of air, and started breathing through his nose.
He looked around the room, seeing what appeared to be walls made of flesh and bone, and a scent that was of rotting corpses. He stood up, wavering on unsteady legs, and turned around to see that he was in what appeared to be a rather large library.
Pharaun saw a large figure sitting in a bone chair about fifty meters away from him, examining a tome of flesh with a pair of spectacles. It was the ultroloth that Pharaun had slain what felt like centuries ago, and he was alive and well.
The yugoloth's head peered up from the book, and he spoke in bassal tones "Ah, you're alive. I would like to thank you for showing me that little trick about the energy field and the delayed blast fireball. I must admit, you are incredibly resourceful. Now, Pharaun, I wish for you to get your revenge."
Pharaun's eyes widened, and he looked up at the ultroloth, trying to form words with his nonresponsive mouth.
"I understand," the yugoloth replied. "You must get used to your new body, and then we shall speak."
A week passed, with Pharaun growing stronger by the day, eventually learning how to speak and cast basic cantrips once again.
One day, shortly after Pharaun ate a meal of barely palpable food, he approached the ultroloth, whose name he had learned to be Inthracis, at his desk.
He stammered the basic words, still not used to these new vocal cords. "Lord Inthracis, I have so many questions to ask you."
He was cut off shortly by a wave of a clawed hand. Inthracis turned around, using an ingenious chair that was able to rotate whenever Inthracis felt the need to turn to another desk. The yugoloth removed his spectacles. "Yes, Pharaun, I know all the questions you want answers to. First off, I am here because of a highly advanced cloning process that took me centuries to perfect.
"You are only here on the good graces of that dear alu, Aliisza, and by sheer dumb luck that the spiders did not eat your finger. I am a fleshmason, which means I was able to reconstruct your body, and find a way to bring you back to life. I have only resurrected you because you are going to be the only one who is able to regain your former seat of power, and perhaps something more."
Pharaun nodded, understanding completely. "The nature of chaos. Turning a former enemy into a new ally."
"Precisely. Now, If you are going to stop that pompous bitch, Quenthel, you are going to need my help. It has been four tendays since she left you to die, and It will be several years before you can get back to Menzoberranzan."
"I'm assuming this is an arcane library?"
"Very perceptive, just as in your last life. Through this library, you shall expand your knowledge, making you the deadliest wizard in the whole of the Underdark, and in some parts of the Abyss too."
Pharaun smiled at the thought of sweet revenge. "When do we start?"
Inthracis returned the smile.
So Pharaun's new training began.
I know. I got the idea from Dark Elf, but this shit is going to go down!