This all pre-5th edition though. How did we even get to 5, which was 4?
I have no idea on the ordering of the editions. I do own Vampire: The Requiem.
::Reads on Wikipedia::
Original Version of Vampire: The Masquerade - Released 1991
Vampire: The Masquerade Second Edition - Released 1992
Vampire: The Masquerade Revised Edition - Released 1998
Vampire: The Masquerade discontinued and replaced by Vampire: The Requiem - Released 2004
20th Anniversary Edition (Revived Vampire: The Masquerade) - Released 2011
Vampire: The Masquerade 5th Edition - Released 2018 before being pulled from publication.
So I guess Reqiuem is 3rd Edition and the 20th Anniversary is 4th Edition.
Speaking of editions.
A post was made on the Steam forums by someone detailing what 5th edition states about Thinbloods. This makes a number of comments about how their clan and powers work, as well as how they can lower their generation.
Pages 109-113 of the core rules are thin bloods
Almost human
Can only take slight damage in sunlight
Are actually now 14th and 15th and 16th generations
Can exhibit a wide variety of traits with no connection to their supposed generation, a 14th generation maybe to weak to form a blood bond but a 15th generation might still retain the ability to embrace and vice versa.
Clans
Always considered clanless and never suffers any specific clan bane or compulsion.
Damage
Take damage like humans but mend like vampires, they take aggravated damage from not only fire but also slashing and piercing weapons, impalement with a stake does not paralyze them but instead causes massive physical trauma, likely sending them into torpor, once damaged, thin bloods heal according to the rules for vampires.
Disciplines
Thin bloods pioneered and practice the art of thin blood alchemy. This potentially allows them to taste the Disciplines of other kindred... And get more than a taste if they can find the Vitae to fuel those workings.
Additionally whenever a thin blood feeds they gain one dot in one Discipline associated with the Resonance of the blood consumed, together with one level one power in the discipline, if the Resonance is Intense or stronger, they gain an additional dot together with a second power.
No additional powers can be gained this way nor can the rating increase with experience. This Discipline lasts until Hunger reaches 5 or the next feeding.
There is also this
Ways out
Straddling the line between mortality and vampirism, thin-bloods have a choice, while they do not age, and can thus stay thin bloods indefinitely, most of their kind sooner or later chooses the day or the night.
A thin blood who manages to commit diablerie on a "true" kindred absorbs not only their power and spirit but also their linage, turning them into a 13th generation kindred of their victims clan. The Camarilla occasional dangles this prize in front of a dusk born who show themselves capable of running the dirtiest errands and surviving, offering up a Cainite sentenced to a blood hunt as sacrifice.
Conversely, every thin blood knows someone who knows someone who returned to the daylight. The story usually goes that they became mortal by clinging to their humanity until they could hunt down and end their sire, thus ending their curse.
Of course, any mortal who knows about the kindred is a threat to the masquerade.
Literally word for word 5th edition. Hope this helps older versions.
So it seems like Diablerie may actually be an option in the game if the Camarilla aren't as hung up about it as they used to be. It still comes with large downside though, main a large humanity cost and a black-veined aura for a year. Longer if the prey is higher generation than the predator (equal to generation difference). There's also the risk of being possessed/taken over by the vampire you're diablerising if you fail.