The only thing I don't factor in that may come into play is shapeshifter parentage - and I think Targaryens were approaching shapeshifters but just didn't get it right yet -- maybe not; surely the DOOM resulted in the transformational creation of human into Gods -- or dragons into humans I suspect. I think if they did shapeshift they were controlling a lot of things very successfully - people, things, swords, man-made environments (buildings and such-- anything metal, mined -- nothing naturally grown).
I think the greatest once-removed human being is maybe in Essos -- where ever those Valyrians migrated to -- but the Targs were very close to getting the bomb but didn't quite make it I suspect-- they moved away before it happened (DOOM). Targs were hugely seductive -- hypnotic and mesmerizing - well enough left alone in Westeros where they could thrive on their prey -- in an agreement, or pact with the Othyrs (not the First Men and CotF -- this is a false pact). Thus why their warg target is humans -- not dragons as some think. Dragons are a red herring mislead. Yeah, they control dragon - heck Targ's control all that is natural beneath them - but they couldn't control The Othyrs (White Walkers).
In an experiment gone totally wrong (or right, depending on your perspective), The Others are dragons in human form (shapeshifters of sorts) who found a way to become human. QyBorg should really be the device tool to explain these unnatural processes-- it'd be cool if he even went there (well, he has in a way with Qyberenstein's Monster). As White Walkers never have a shadow and are not seen during the day they must be dragonsl I suspect like Bran and BR they are never really physically in a place, but they are ice-seeing their locations and controlling wights much like MORDOR controls all things evil. They (WW's/Othyrs) were fine and dandy up in the far North until Free Folk were pushed far North and took CotF lands, thenn the CotF failed to flourish. Othyrs now having a depleted food supply and must migrate South towards Dorne and the Orphans of Greenblood-- with civilization in the way. All this could be fixed if the humans just get out of the way (LOL .. no it can't. WW's want to restore Westeros back to original configeration -- defreg, delete all, re-install fresh.
Purple Haze -- Prince was a genius and will be missed.