This may sound like a stupid question, but I have check the Imperial Libraries and any Necromancer Books in Morrowind/Oblivion. But Who/What is N'Gasta? Is there any pure information or pictures of him/her? Is N'Gasta a Sload?

Any help would be appreciated from you local lore masters

Yes, N'Gasta is/was a Sload. He was a character in Redguard, and used a sort of soul net to trap souls for Clavicus Vile, if I recall correctly.

Yep, he's a Sload. Here's a little http://www.imperial-library.info/tsorg/part10.shtml from Redguard, including a picture (scroll down).

That's interesting.

Slug + Necromancer + No personality

Not great at parties I presume.

You might be surprised indeed! While I find necromancers as a whole to be somewhat singleminded, the Sload themselves could tell some remarkably bawdy tales. The stories themselves were not the draw, mind you, but the Sload had no shame about who and where they spoke of these things. Even today, in certain high society gatherings, you can tell a dirty or shocking story by the preface "A Sload once told me...".