The link below shows the Skaven Necromancer as he first came into the world:
https://twitter.com/FGONeill/status/552775780921389056
Over time, surviving 20-30 quests, he evolved quite a bit. He first stopped having to search for treasure whenever he could (the other Heroes were rubbing off on him); then, he learned the Spell Token spells from Against the Ogre Horde (the reward of surviving that quest line); as he became a long-tenured and beloved Hero, he gained the Voldemort-like ability of reanimating in the body of his current thrall but at a quest-long reduction of one body point; then, he could reanimate fallen Orcs into Skeletons if he was without a thrall; and lastly, his starting Skaven Thrall got an extra point across the board and all three fire spells.
He finally met his demise (along with the then-current Elf and Dwarf) at the hands of one of Sinestra's Chaos-Spell-wielding lieutenants:
https://twitter.com/FGONeill/status/596645244084453376