I Read the PnP rule book sometime long ago but that is all and I don't recall much from it so I'm mostly thinking about stuff from this game.
A "regent" in V:tM is the head of a Tremere chantry. JFYI.
The "taint" manifests as things like residual personality traits, and the person's soul fighting against yours in general if it's strong.
And Tremere usually wish to consider themselves the rulers of the city. But whatever bloodline the vampire is from there is a leader of that line in the city who got rules they want obeyed.
The residual traits might be worth it unless one becomes erratic, schizophrenic or go mad.
And yes, vampires have souls. Otherwise they'd be, what, zombies?
Well, actually yeah. Just like ghouls, zombies, skeletons and whatever other undead abomination you can find.
I seem to recall that in this work of fiction it is the blood that matters, the body is a husk to house it with the exception of the heart.
By this logic, a human that makes another human is called a parent, making the new human his parentling. In other words, no, that's not how words work. For the record, the term in V:tM is "childe" (the game's full of sorta-pretentious stuff in its lexicon).
http://dictionary.reference.com/browse/sireI seem to recall that in the opening sequence of this game they talk about this.
Except if you don't try to stay human, you end up sliding down a slope leading to complete corruption by The Beast really, really, quickly, and end up an unthinking monster who has to be put down.
I did not elaborate that enough.
Compare it to the vampires in the movie "Interview with the Vampire: The Vampire Chronicles". Where one refuses to drink from humans, trying to stick to human morals.
With 'within the limits of the masquerade' I ment to avoid just that which you described.
My point being - If you can get away with diablerie by being calculative in your actions and the consequences, It seemed a fast way to increase your strength.
And now I will go search for a pdf of the rulebook and see if my memory wrongs me.