Why did the Lich King create the San'layn?

I was replying to a post in wow forums ( [You must be registered and logged in to see this link.] ) and it did get me to wonder, that Lich King had a wide repertoire of undead servants. Most of them were merelty animated from different species and races. Then there were lesser units such as ghouls and shades which were not race specific ( I think ). Then there were stronger beings such as Liches who were potent casters and death knights who served as elite footsoldiers and commanders.

My question is: what did the san'layn bring to the table that others did not? Why did he create them? Why was there so little of them? What do you think?

Becouse when making a undead army why not add a bunch of vampire like things you got to have your bloodsucking undead in there somewhere!

It's true there are a lot of already blood/life drain things out there, but I guess you just need your "vampires" or a form of them in the game.

But if we're going for story reasons, well they aparently are good at infiltrating the humans back in borean tundra far as i can remember and are good at manipulating them. Since they were blood elves mainly and kael'thases forces you already got good spellcasters, the vampiric theme is just there as an added bonus i supose or irony?

Far as the numbers go LK raised some of the stronger forces of Kael'thas to make them into this one specific thing and he obviously didn't mass produce them becouse the scourge already had mass produce soldiers.

Just think of it like the LK walked around with a roulette if he met strong peeps he rolled it and decided what theme/power he'd give to these newly raised dead. Of course if it was just footsoldiers you'd just raise them as footsoldiers you're not gonna waste your time on tom the farmer, becouse tom the ghoul works just fine considering his previous occupation. On the other hand XYZ the super mage or Jane Doe the mighty knight of light get a chance of becoming some higher top soldiers with some distinctive power depending on the LK's sense of humor.

Story reasons or more likely LK's pov is what I was wondering. I think Blizzards view is quite obvious since no undead army is complete without some pop-culture bloodsuckers. Oh and they now finally added their vampyrs in Stormheim!

Infiltration and manipulation might be the thing of San'layn. And it was Illidan's belfs that were turned into them. But from infiltration point of view would it not be more useful to turn some humans into san'layn also? Is there some specific reason why they are all elves? Are those fel addicted long ears more prone to always turn into some sort of addicts (blood in this case maybe)? Also when looking at Blood Queen Lanathel's abilities they kinda hint towards some sort of mind controlling trough enhancements delivered with bites.

What I've been thinking is that San'layn could have been blood magic specialists of the Scourge. As I read from wow.gamepedia about blood magic and it appears that the nature of blood magic is a gruesome solution when you need to survive extreme conditions (look at the Sandfuy).

I think it has been stated that every form of Undeath comes with some kind of addiction (Ghouls, Zombies etc eating fresh corpses of sentient races, Death Knights with Pain and Destruction etc) so... I dunno, if the LK had control over it maybe he took it as a sort of sweet irony?

Or perhaps the Elves were just a natural choice and that's how their form of Undeath "evolved" (think I read somewhere before that a Ghoul is a "final form" of a zombie but I could just be remembering wrong).

Either way, their purpose was manipulation and infiltration as mentioned but I do believe they also served as "diplomats" of sorts, considering what they were doing with the Vrykul anyway. Also maybe strategists where as the DK's were more a "battlefield" commander, they actually send the orders.

Either way, Undeath is one hell of a drug.

I think hutch nailed it there on the blood drinking thing, with nearly all undead needing to consume to stay functional

Even the ones that don't have a crutch in another format like a Lich who probably is paranoid as fuck 24/7 thinking who's gonna try brake his Phylactery which sustains him

With them few exceptions like the Lich being rare it seems pretty easy to presume that without something else to keep you working you need to take from the living to work in some form.

Not sure about DK if there needs were implemented by the Lich king to control them rather than being a requirement for them otherwise,  seems logical to me that they were made like that more for practicality of service as I can't see another reason.

On our vampire blood sucking buddy's though there's not as much difference between what they do to stay undead as most really. bar looking more sophisticated drinking blood out of a glass over chomping down some dead guys guts in a ditch they are still consuming people

They are smart sophisticated and good smooth talkers, guess that makes them fit a role that most undead just are not that great for,  there's not a lot of undead that tend to be very socially skilled