All rare drops will be given variables that bind them to the number of trials it takes for them to drop. When this variable reaches its potential, it drops an item for the player and resets, potentially to a higher value to prevent inflation of that item. Lets say that I'm grinding for black kats, and my variable needs to reach 237, as these variables will likely have some degree of randomness added into them. On my 237th black kat, I WILL receive the book of dark rituals. No sooner, no later. From my perspective, it was a simple random chance, but from the server's perspective, it was set in stone all along.
The strengths of such a system
Where would it be used?
First and foremost, the black kat cowl should be mentioned along with the darkfang shield, as both of these are currently sorely lacking such a system. Along with that, true love lockets and other rare monster drops could be tweaked accordingly.
After that, there are a number of other drops that could be added in- knights at a rank could be made likely to find at least one piece of random 3* armor, while knights above a certain rank could be given an easier time finding a certain rare rarity.
Finally, new items could easily be implemented to fulfill this and make the game a better place. Maulos's maul was recently rumored to exist in game, as well as vanaduke's maul, the "third troika", and a good many costume armors that could easily be reskinned to fit into danger rooms and other such places.... While these may not be necessary, implementing them as findable loot would go a long way in the game's original image, and a longer way towards improving the game's product of old school fun.
Please read the comments below! Dahall suggests a very interesting and better version of my idea, and we discuss it!
Here's a slightly better one.
Let's say a rare item has a 0.01% of dropping in a level. If that item fails to drop in that level, the chance of that item appearing increases by it's default value(or doubles) until it has dropped successfully after which the drop chance will reset to the default value.
Then not only will it be a drop by chance (instead of a fixed amount of grinding) but it will also ensure that players are rewarded eventually.