This is fanfic.
There is absolutely nothing in lore linking Volkihar to summoning gargoyles, there is absolutely nothing in lore about Volkihar transforming themselves into another form.

There is no reason to link the Volkihar to the Purebloods, they are most likely seperate strains as the behaviour and powers of the Purebloods differs wildly from that of the Volkihar.

Please dont post fanfic and claim its proof.

Better two strains than broken lore.
They behave very different from Volkihar as described and their powers are very different from Volkihar as described.
Thirdly, it doesnt make any real sense for a Pureblood vampire to be a Volihar as nothing in lore names Volkihar especially powerful, old, or talks about any engagement with any Daedra.

If you listen to Serana she has been a vampire since sometime in the first era so it is plausible for the pure bloods in the castle to be the first of their kind. It isn't impossible for the thin bloods to have developed differently over the hundreds of years living in the wilds as exiles just as any other creature would eventually adapt to survive best in its environment. For all we know Volkihar could be Harkons surname and the exiles just kept and used the name Volkihar being it is where the disease originated.

lol I never noticed that there was never a mention of Harkon's surname. That's really weird, come to think about it...

You think I don't know that? Me, especially? Stop kidding yourself.

I know. I don't agree that the bugaboos of Harkon's circus are the Volkihar, but simple took the name of the Castle and kept it.

I realize this, and I also do believe purebloods not only exist in Skyrim. They are seperate strains, as Lamae was a Pureblood and the ones she begat most likely took a different course throughout the years.

Please don't compare me to the children. I just posted content from the UESP, and no matter how many times I changed it before, someone inexperienced in vampiric lore always comes in and changes it. Don't you dare insult me of not knowing about what I truly like in the Elder Scrolls.

Wait, if the game puts a sign over your head that labels you 'Volkihar', doesn't that mean you're Volkihar?
The lore doesn't have to be broken for the majority of vampires in Skyrim to be Volkihar. All that's required is for the book Immortal Blood to have been written by a Vampire who was exercising his vampiric nature and writing a book designed to deliberately confuse and conceal the truth.

The point is that there is no sign over Harkon's head.
At all.
Once again, the only reference to the Volkihar in the entire DLC is the name of the castle. That is it.
The name of a castle doesnt mean that the people living there have that name.

I still kinda think that the book Immortal Blood will turn out to be a deliberate obfuscation of the facts about Vampires by its Vampire author - if you put a lie in with the truth, those that know the truth will recognise it (and so identify the author as a genuine Vampire), and those who do not know the truth will be unsure of what to believe.

At least the entire issue of heritage and background in the DLC is ambiguous enough that we all get to believe what we want.

All of the Vampire NPCs in Volkihar Castle are named NPCs, so not having the generic label doesn't mean they are not Volkihar vampires. The game labeling NPCs as 'Volkihar' means they intended those Vampires to be perceived as Volkihar. Those generic NPCs don't have any observable abilities that equate with the Volkihar Vampires in Immortal Blood either. The Vampire Lord ability is proof to me that the generic NPC Vampires are not the same as the castle Vampires, but I wish at least one other NPC in the castle actually used the ability as proof that they were all like Harkon.

Does the mist ability in the Vampire tree work in any kind of situation where it could be interpreted as 'phasing'?

I still kinda think that the book Immortal Blood will turn out to be a deliberate obfuscation of the facts about Vampires by its Vampire author - if you put a lie in with the truth, those that know the truth will recognise it (and so identify the author as a genuine Vampire), and those who do not know the truth will be unsure of what to believe.

At least the entire issue of heritage and background in the DLC is ambiguous enough that we all get to believe what we want.

On top of that, isn't Movarth's Skyrim race different from the one in the book? Hmmmm...

On top of that, isn't Movarth's Skyrim race different from the one in the book? Hmmmm...

On top of that, isn't Movarth's Skyrim race different from the one in the book? Hmmmm...

I always just RP'd when my Volkihar character gets to that Movarth quest line that The Order is trying to move in on my clan's territory so I make it my mission to wipe them all out.

No.
All vampires in Skyrim are the same, regardless of clan.
Even the Dawnguard vampires have the same abilities and weaknesses as any other vampire.
Except Harkon, who transforms into a vampire lord on two scripted occasions and nowhere else.
If you attack him outside of those two scripted events, he will not turn.

Gameplay isnt lore.

*facepalm*

I was referring to his race. As in Breton, or Imperial. Or maybe I'm mistaken.

Oh I see.
Well, before Dawnguard he was a random male and could be any race.
Since Dawnguard this is fixed but I dont know if his race matches what is in the book.

The point is that there is no sign over Harkon's head.
At all.
Once again, the only reference to the Volkihar in the entire DLC is the name of the castle. That is it.
The name of a castle doesnt mean that the people living there have that name.
IRL our royals live in castle Drakenstein (from time to time) but they are called van Oranje- Nassau.

The vampires of http://www.uesp.net/wiki/Lore:Tamriel are commonly grouped by their territory and "bloodline". A vampire's bloodline is determined by the vampire who infected it, which in turn affects its abilities. Some vampires have created clans according to bloodline and territory. These clans normally consist of vampires of the same bloodline, or who share the same feeding grounds. Some clans are powerful enough to have established strongholds and captured "cattle": prisoners who they feed off of without turning them into vampires.^{http://www.uesp.net/wiki/Lore:Vampire#cite_note-18}

Black Marsh

The Whet-Fang vampires of http://www.uesp.net/wiki/Lore:Black_Marsh are known to capture victims alive and keep them in a magicka-induced coma, allowing the vampires to extract blood at their own leisure.^{http://www.uesp.net/wiki/Lore:Vampire#cite_note-Manifesto-19}The Order vampires of Cyrodiil believe the Whet-Fang vampires to show "signs of enlightenments", regarding them as more intelligent than the other "barbaric" tribes. For this reason, the Order considers them a possible threat to their dominance in Cyrodiil.^{http://www.uesp.net/wiki/Lore:Vampire#cite_note-Manifesto-19}

Cyrodiil

Only one known tribe exists in http://www.uesp.net/wiki/Lore:Cyrodiil; they are experts of concealment, their true name lost in history. Much like the http://www.uesp.net/wiki/Lore:Imperial, they ousted their competition. Indistinguishable from the living if well-fed, these Cyrodiilic Vampires are cultured and more civilized than vampires of other provinces, using their stealthy abilities to feed on the sleeping and unaware. Calling themselves the Order, they have made Cyrodiil their home as of the Third Era, and, in accordance with their strict tenets, these vampires follow the Daedric Princes Molag Bal and http://www.uesp.net/wiki/Lore:Clavicus_Vile. The clan is made up by upstanding members of society; politicians, nobles, aristocrats, counts. From their offices of power, they manipulate the hand of society to meet their agendas. They have a thirst for blood that matches their hunger for power.

High Rock

The Glenmoril Wyrd vampires live in the Breton cities of http://www.uesp.net/wiki/Lore:High_Rock, though no information about their abilities or feeding habits is known. It is known, however, that they are one of tribes considered more intelligent by the Order vampires of Cyrodiil; possibly implying that, like the Order, they live among the normal population as stealthy manipulators.

Iliac Bay

The http://www.uesp.net/wiki/Lore:Iliac_Bay region hosts nine bloodlines of vampires, each with their own special abilities: the http://www.uesp.net/wiki/Lore:Anthotis, http://www.uesp.net/wiki/Lore:Garlythi, http://www.uesp.net/wiki/Lore:Haarvenu, http://www.uesp.net/wiki/Lore:Khulari, http://www.uesp.net/wiki/Lore:Lyrezi, http://www.uesp.net/wiki/Lore:Montalion, http://www.uesp.net/wiki/Lore:Selenu, http://www.uesp.net/wiki/Lore:Thrafey, and http://www.uesp.net/wiki/Lore:Vraseth. The clans inhabit their own regions, and a strong sense of rivalry is present.

Skyrim

The Volkihar vampires of eastern http://www.uesp.net/wiki/Lore:Skyrim live under haunted, frozen lakes and only leave their dens to feed. They have the power to freeze their victims with icy breath, and can reach through the ice of their frozen lake dens without breaking the ice. They are the earliest known vampire coven in Tamriel. The Volkihar vampires are relatively similar in appearance to those of Cyrodiil and they share some similar powers such as night vision, the ability to turn invisible and the ability to seduce others. Certain Volkihar vampires however appear more monstrous than their Cyrodiilic counterparts- some of them have large brow ridges, slits running through their lips, and bat-like noses. They can reanimate dead bodies and do not burn when in sunlight (although they are weakened by it). Some of the more ancient Volkihar vampires such as those of the http://www.uesp.net/wiki/Skyrim:Volkihar_Vampire_Clan at http://www.uesp.net/wiki/Skyrim:Volkihar_Keep can even transform themselves into a more monstrous form: the large, winged http://www.uesp.net/wiki/Lore:Bestiary_V#Vampire_Lord form which grants them further powers such as the ability to summon http://www.uesp.net/wiki/Lore:Gargoyle.

Valenwood

In northern http://www.uesp.net/wiki/Lore:Valenwood, there are the Bonsamu vampires which are indistinguishable from normal http://www.uesp.net/wiki/Lore:Bosmer unless seen by candlelight, the Keelrlith who can disintegrate into mist, the Yekef who swallow men whole, and the Telboth who prey on children, take their place in the family, and eventually murder all of the family members.

Vvardenfell

The vampires of http://www.uesp.net/wiki/Lore:Vvardenfell are distinguished by three bloodlines, which differ in accordance to their "approach to prey". The http://www.uesp.net/wiki/Lore:Clan_Quarra are aggressive and fierce when it comes to hunting, while the http://www.uesp.net/wiki/Lore:Clan_Berne clan prefer a stealthier approach. The http://www.uesp.net/wiki/Lore:Clan_Aundae bloodline consist of vampiric mages, who use the dark powers associated with vampirism to entrap prey. These vampires not only have their own strongholds, but are also dispersed amongst the Daedric shrines and abandoned Dunmer and http://www.uesp.net/wiki/Lore:Dwemer strongholds.^{http://www.uesp.net/wiki/Lore:Vampire#cite_note-Blasphemous_Revenants-16} Ironically, these clans show great hostility to new-born vampires, considering them abominations as their living counterparts do.

And again alot of NPC's are called Volkihar vampires, and as you said all the vampires are the same bloodline in skyrim because they all share the same qualities. So still, not the only reference to Volkihar.

There's no sign over our head either saying we're the dragon born but we don't need one to know ;p

I never said all vampires in Skyrim are the same bloodline. I said there are at least two bloodlines and likely three present in Skyrim.
I did say that all Skyrim vampires share the same mechanics, have the same abilities. Gameplay is not lore.

There is a sign over our head saying were Dragonborn.
We are called Dragonborn numerous times. We have the abilities of a Dragonborn.

For Harkon, no such reference exists.

All the vampires outside of the castle are referred to as thin blooded mistakes that were pretty much related to the ones in the castle though

Does the mist ability in the Vampire tree work in any kind of situation where it could be interpreted as 'phasing'?

I still kinda think that the book Immortal Blood will turn out to be a deliberate obfuscation of the facts about Vampires by its Vampire author - if you put a lie in with the truth, those that know the truth will recognise it (and so identify the author as a genuine Vampire), and those who do not know the truth will be unsure of what to believe.

At least the entire issue of heritage and background in the DLC is ambiguous enough that we all get to believe what we want.

This is an excellent point. Its important to remember that everything we know about the Volkihar comes from IB. Its also entirely possible that the priest was (as W&V suggested) creating a pawn to kill off other vamps. What I've always found interesting is that the priest's info on the other clans was accurate except with the Volkihar - Movarth had to correct him. This suggests he knew and was trying to kill Movarth, knew and was testing his adaptability (as a possible future pawn), or did not know at all. Of course the entire premise of the book is in question. Why would a member of the Order have it printed? It could have been a novel or (as suggested above) a dis-information campaign. The fact the Movarth is an actual person opens several interesting possibilities. My point is we may want to consider that the information in IB is not completely accurate. And on a meta-anolysis level the book is there to explain why vampires in Oblivion can walk unseen among mortals versus the three clans in Morrowind.

I dont recall that dialogue.

In any case, Morvath and his gang are known to be Order vampires, as the vampire that turned Morvath was one.
The other strain that we definitely know is in Skyrim is the Volkihar, the game names certain NPC's so.

There is however nothing that says or even makes plausible that Harkon is a Volkihar.