
So I'm going to try running another Zoom AD&D game again with a group of old friends I've known from grade school. We'd stopped playing for awhile because of attendance issues and what not, but that seems fixed. And with Halloween season coming (I refer to Oct. 1st thru 31st as Halloween "season"), I had an idea of incorporating vampires into the game with inspiration from the old Hammer Horror film Legend of the Seven Golden Vampires (titled The Seven Brothers Meet Dracula in the USA and Seven Kung Fu Brothers and Their Sister Kick Dracula's Ass by an irreverent friend of mine

The problem is level drains. The players are mature enough not to have problems with level drains. These guys don't even like resurrections. You die, they wanna roll up a new character. Old school guy!

So I'm trying to figure out an easier (more efficient) way to run this without watering down level drain. At a tabletop game where we're trying a long term ongoing campaign where the PCs are concerned with story and character development over advancement, this isn't an issue - we'd just use level drain BTB. But this is a campaign we're not taking too seriously, just a fun go-out-and-adventure sorta game.
I want to keep it potent, so I'm trying to figure out a system for it. I was thinking of having each level drain (for each level) take off 20% of current hit points. So for a ghoul it would take off 10% of hit points but a vampire on one hit would take off 40% of current hit points. Sure, the 3rd hit kills the character, but they're all 6th level, so 3 hits using the BTB rules kills them as well. Not really any more deadly than going BTB. I was also considering just adding a +2 penalty to thaco and damage per hit (for a vampire - it would be a +1 penalty for say a ghoul).
So looking at a generic 6th level fighter (I'll ignore any STR or CON bonuses to make this easier), he'll have a THACO 15 and an average of 33 hp. The first hit of the vampire would drain 40% (13 hp rounded up) of his original 33 hp, leaving him with 20 hp and a THACO of 17. On the next hit, he loses 13 hp (20% of the original 33 hp) leaving him with 13 hp and a THACO of 19. A third hit would take off another 13 hp, which kills him.
I think that system would work fine and be simple enough for everyone to use and it makes vampires still a really tough threat. I'm also considering a long term CON deduction or perhaps it would be easier to simply make it where magical healing does not work on hp lost to level drain - those hp have to be healed naturally through rest. That might be easier than a CON deduction.
What I'm having trouble with is how to handle spell loss. That's a fucking can of worms. A simple method would be to lose access to spells of a certain level with each touch. So for example, 6th level wizards get access to 3rd level spells. Therefore, the first touch of the vampire would remove their ability to cast 3rd level spells, the next touch removes their ability to cast 2nd level spells, and the third touch kills them anyway, so losing 1st level spells is moot. Using the BTB rules, a character may still be able to cast spells of each level, but not as many of them, which complicates the matter. There are a lot of methods to determine which they lose (they lose random spells, they lose spells picked by the DM, they lose spells most often or least often used, etc). But regardless of how that is determined, it's a fucking hassle. So I'm thinking simply losing an entire level of spells with each drain makes it very simple and also very potent.
I've also thought about making each hit of the vampire drain 1 level instead of 2, but giving them 2 attacks per round. I'm not sure if that's better, worse, or no different than just keeping it at 2 levels drained and only 1 attack per round. I was thinking that doing so would make ALL level drains equal, except that some monsters (like vampires) can attack twice per round. Granted, each drain is less potent, but they could drain 2 different characters per round. I wonder how that would play out? The idea just popped into my head as I was writing this. What do you guys think?