If that is the case then I must first ask why Vlad and Isabella but not Mannfred? It's been heavily implied in the fluff that Mannfred was or still is an agent of Nagash (willing or unwilling) so it would make more sense for him to be there.
Vlad and Isabella existed in the 4th edition book, and Vampires are undead so I wanted some Vampire special characters. As far as Mannfred goes I didn't want to include all the Vampire special characters from 4th and since Arkhan fills the role of the powerful spellcasting special character Lord, Mannfred isn't necessary. So I chose Vlad (and by default Isabella) over Mannfred for the simple reason of game balance. Coming up with fluffy ways of justifying stuff is easy, as a matter of fact in the 20 years that I've been into Warhammer GW has contradicted their fluff on numerous occasions. Liches in my list are the most point costly characters and the most powerful wizards as Liche Kings in Kings Of War are.
Which brings me to another point, if this is a Nagash themed armybook then the core of their Lords and Heroes should be Liches, Necromancers and Wights with Vampires and Tomb Kings as rare heroes of the Army, especially the Tomb Kings. Why? It goes back to the fluff they've established since that first book.
I should have titled this thread 4th edition undead/Kings Of War Undead for 8th edition Warhammer, but I wanted to keep it short. In Kings Of War Vampires are the most powerful fighty characters where Liche Kings are the most powerful spellcasters. You can't make a powerful fighty Hero that stands up to a powerful fighty Lord. As far as the fluff of the 1st book, 4th edition was when they first started making army books. In the 4th edition undead book that is sitting right in front of me although Lords as a unit type didn't exist, Vampires are right up there in power level and point cost to Liches. I am ignoring fluff right now because I'd rather focus on a fair and playable list that captures KOW elements as well as 4th edition elements in a balanced and fun 8th edition army.
First the Tomb Kings and their armies, while Nagash did create them and initially had control over them he lost it when Alcadizaar slew him. When he returned 1111 years later he tried to regain control over them but instead they drove Nagash from their lands. The vast majority of them HATE Nagash for what he's done. Only a small minority of Tomb Kings would serve Nagash and even then they'd be very careful about lest Settra and the other Kings learn of this. The only reason they tolerate Arkhan the Black in Nehekhara is solely because he's the only one that rivals Settra. Some Kings simply hate Settra more than Arkhan and see the value in keeping someone that can oppose Settra. But that is not the same as supporting Nagash. They united under Settra to drive him out once before, they will certainly do so again.
Wow that was really interesting, I should get around to reading the fluff in the Tomb Kings army book I picked up last week. Again with the fluff, let it go. I am looking for rules and balance input right now. Preferrably from people who are familiar withh both the 4th edition Undead Army Book as well as the current Kings Of War Undead army list. If I want to read a story I will pick up a book.
As to the Vampires, some do serve Nagash (certainly far more than the Tomb Kings that serve him) but at the same time they and Nagash have some bad blood between, dating back to the time when he still walked the world. One time the Vampires did ally themselves with Nagash but the majority of them abandoned him when things started to look bad and in return Nagash laid a curse of weakness upon them, giving them one more vulnerability.
You wish to use them in the army fine but I'd say do so with restrictions, like maybe one TK per army, or how about a Tomb King being a Hero choice with a statline the more closely resembles a Tomb Prince... oh wait that's what I did
they can't be the General with the exception of characters, etc...I am pretty sure only a character can be a general, and if you mean only special characters can be the general and generic characters will have a bunch of crazy wierd stipulations that normally only special characters would have then that is just silly
Instead of having them be the CC characters of the army look to the Wights. Hmm I assume that now we are talking about Vampires I missed the subject change from Tomb Kings. Again Kings Of War Vampires are the best fighty characters, I am trying to keep that element since I am trying to make a list using models I currently posess. Furthermore Wights (a fighty hero) is a poor substitute for a Vampire Lord.
Who's to say that all of Nagash mortal followers have to be Necromancers? While he certainly needs magic users to maintain his armies he also needs those with tactical minds. Just because you have incredible magical power does not mean you have a gifted military mind. Arkhan has been unable to defeat Settra despite his magical prowess simply because Settra has the greater army and a superior military mind. I could see Nagash or his agents attracting great warriors that desire immortality to their side and then those that serve especially well are rewarded with the transformation into a superior kind of Wight that retains their intelligence.
If they retain they're intelligence they could eventually try to overthrow, it is easier to have absolute control over your followers through Necromancy, or be able to control them through their weaknesses like Vampires Blood Thirst and susceptibility to sunlight. Furthermore I am trying to use as many already existing units as possible instead of creating new ones since their game balance, statline, and point cost is already established.
Or instead of Vampires you could have the return of the proto-Vampire, Nagash's Immortals. About the only difference between them is they would not have the Hunger and some of the Vampire Powers.
I like The Hunger because it is not very powerful and adds a certain flavor to vampire characters in the game, setting them apart from just a necromancer with armor and a beefy statline. As far as the Vampiric Powers go they have been renamed Dark Powers and all characters in the army that are supernatural but have free will have access to them. That of course being Liches and Vampires
I also think you could stand to thin out your cavalry units as you have four plus the chariots in your army. I'd get rid of the Skeleton Horsemen and Horse Archers while bumping the Chariots to Special. With the Dire Wolves in the list there's no reason for those two as they more or less play the same role in TK and VC armies (Horsemen, not the Chariots). Skeletal horsemen with the option of taking bows and Wight Cavalry were in the 4th edition book. I have been thinking about changing them to be a single unit of Skeletal Horsemen with a bow option, and dropping the scout rule. I am confused at how you figure that Fast Cavalry with bows serve the same role as War Beasts they are different types of units with very different functions. The chariot units were originally going to be a special, a friend talked me out of it, but I plan on switching them back to such. Wight Cavalry are an integral part of the army and they aren't going anywhere. Blood Knights were not in 4th edition army book but they have an equivalent in Kings Of War so they aren't going anywhere.
Similarly I think you should rethink the Mummy units of the army. Let's face it most mummies are Tomb Kings now or to a lesser degree some Wights. I say use that. Mummification is why the Tomb Kings retain their intelligence while the Wight Kings do not typically have theirs preserved. Have mummification as a upgrade for one Wight unit per army, boosting their stats and price.
Yeah mummies are Tomb Kings in the Tomb Kings book, however they are just a regiment in 4th edition Undead and in Kings Of War. Since they are meant to play a lesser role in this list and be relatively rare, they are a Rare choice regiment. Also since I have a regiment of rather plain looking classic horror style Reaper Mummies I plan on keeping the unit as it is. If they didn't make them into characters for Tomb Kings, then your army which was a rather late addition to the game (6th edition is when they first appeared) wouldn't have much in the way of character choices.