Gangrel get two forms with their basic protean abilities. One is their fight/war form, the other is their flight/run away form. This is basic ability. Later, and yes I believe it is 6th or lower, they get a scarier form on par with the Zulo. In any case, the term Warform is coined here as a form that enhances the vampire for combat purposes. Gangrels are vicious with their claws in human or war form. What is interesting is that only Gangrel get to choose something other than wolf and bat for their protean ability. Other clans that somehow pick that up will have wolf and bat. I think the rationale in that, is that it is wired into their imaginations and or mentally that they can only assume those forms, where as Gangrel can choose. Yet they only get 1 battle form and 1 run away form. The two forms originate from the beast instinct of fight or flight and flight does not HAVE to be a bat or bird, it could be some kind of other form that is an escape form(for Gangrel)
Referring back to Fabian, I certainly did not mean to assert that he is ancient like Calisto. The scene the MC sees is clearly middle/dark ages and he is a knight. That probably fits his approximate time of turning. The only other vampire we have a hint of real age about so far is Virgil whose name is Plubius, or at least he offers as much to Sharon. That is definitely Roman time frame in terms of naming.
Clans vs Bloodlines can certainly get messy. And yes it is my own head canon at the moment that Astrid represents a differing pantheon as Astrid is a prevalent Norse name in their mythology. It would also be a very nice step away from VTM to have the vampires rooted in the differing pantheons, so that appeals to me. The very fact that Sharon dismisses both Fabian and his Thaumaturges along with the Pagan cult is so very Sharon like, I find myself amused.
Astrid being the current "evil" that we have to go on, it is natural to speculate on her origin and her power level. Vision Girl being who she appears to be, is likely to be very unkindly disposed to anyone who means harm to her plans, and thus I am thinking that she might have been working on this (including the MC embrace) for a while. Kassandra is not a name thrown about lightly, nor are any of the steadily growing list of Greco-Roman names. It is easy to conceive of Kassandra's role in this to be one of screening and recommending candidates for the next Calisto childe.
So to overly complicate things is probably a mistake, and to over simplify also seems to be a mistake.
What we know vs what we do not know, has not really helped us out much in the theory crafting here.
While you make a point that Ventrue do not single out babysitter types as their typical childe, neither do we have an abundance of artistic talent displayed by Sharon either. Kassandra is the only one that is in an artistic like field, running night clubs, but she is not alone in this and she says as much.
The hound... Eloise, is definitely Ventrue material, and Sharon comes right out and says that the MC could be one of "Us". Take that with the inferred Fortitude, the not inferred but directly exercised Presence, and the most popular of Sharon's powers Dominate, we have a text book Ventrue.
Sharon also tells the MC right off to work on income and power base, as he will need both. He retorts being a DJ, and she dismissively moves on from that. Sharon clearly either comes from money or made a lot on her own as her place in the city is quite nice, and she doesn't fret at all about having to buy a new place in Scottstown when it is brought up as a possibility by Andrew.
I would wager my own left nut that she is as close to what passes for Ventrue in this novel, as there is.
Astrid..... Clearly Sharon states "Her Kind can do that" when talking about looking alive. One of the most interesting abilities in Vicissitude is the ability to look alive, or super humanly beautiful, or ugly, or other worldly. Perfection of the form, whatever that may be, is the goal of that discipline. Now 5th edition is combining Koldunic Sorcery and Fleshcrafting into one clan morphing of the Protean Path for the Tzimisce. Now I personally am not sure I care for it, but it is quite interesting. Tzimisce are traditionally so tied to the land of their birth, that they must rest on two handfuls of soil from that land. Not quite so much in the current edition, as the Fleshcrafters move away from the lands of their birth with little to no impact, and the Koldunes become One with the Land, in essence becoming almost like spirits that serve Gaia of all things.. I think they even reference some kind of bizarre connection there that is not Wyrm ridden.
I think Astrid is a shape shifter. Not a were critter. A vampire shifter. As she is clearly not eaten up with Beast Traits, which even Vicissitude can not so easily cover up (or the ugly of the Nos for that matter, I am left with her not being Gangrel. I also believe that she is tied to the place and time of Scottstown at a perfect locale to whack Sharon up side her head when she is on the verge of interrupting Astrid picking up Gregor for her collection. So I think Astrid assaulted Sharon, not simply wanting to kill her, but to humiliate her in court, and sow discord throughout the realm. The kill desire is coming fast though, as her only out, if that.
These are not overly complicated. These are not overly simplified. I think like Goldilocks, it is just right.
We can throw pantheons and such in later if desired, but I think they make a very good talking point. Loki's line of monsters for Tzimisce anyone???????
Peace
