False Hydra Stomach Acid

*For those concerned already at the title, my players and I previously spoke about their characters having amnesia, they just don't know why*

I hate the idea of running a False Hydra. They seem non-playable (someone even said that they are a Video Game villain poorly made into a TTRPG villain. Agreed. But then, as I was putting the finishing touches on my previous campaign's second arc, inspiration struck (due to my entire party deciding that low charisma parties are great at intimidating the literal king), and I started thinking of a way to really utilise the False Hydra, and utilise it well...which meant not actually using a False Hydra. 

The concept is easy: due to interplanar rifts nearly bringing all the planes of existence into one (BBEG of my last campaign), the party put an organisation (for lack of better word) who would police the rifts until the realms healed properly. Obviously, after a couple of centuries, this became corrupt and have begun using the organisations name to essentially take over each of my countries kingdoms. Which means they are really good at what they do, one thing that they also do, is create new stuff to help them on their mission. They are centuries old, so how do they keep their plan for world domination secret? Conveniently getting rid of 'agents' who turn. Of course this would become a hassle when some countries have mandatory military service for Royal families (in countries where the org runs the military). But what if, crazy thought, people just forgot they existed like Taylor in 2019? What if, in order to create my sick need to run a False Hydra could be utilised in a way that meant I don't ever have to play a False Hydra? 

Introducing: False Hydra Stomach Acid! A secret formulae made from, you guessed it, False Hydra Stomach Acid and a really excited DM!

This is not a widely used thing, and in fact only one alchemist knows about it (and they aren't evil, just temporarily blinded by the organisation), so it's not like it's a wide spread thing (just unfortunate that the players were undesirable agents who needed to disappear). The FHSA was used against them because the alchemist wanted to save them instead of having them executed. The organisation conveniently forgot about them, but the FHSA was tweaked so that the party would eventually gain their memories back (with what we are calling memory DCs). My big issue now, is I want the party to have the option of the entire world remembering them, but the FH in question was killed for it's stomach acid, so that's out the window. 

I was just thinking that maybe once they uncover enough of their memories, they can begin reminding everyone and eventually the world will remember (canonically, it's been not even a weak since they had the FHSA). Once you've been innoculated with it, you have a familiarity with anyone else who has taken it (if known before taking it of course), and eventually they'll remember each other. I just don't want the 'cure' for the memory loss to be too hard for them, or not possible at all if that's something they want to do. Or would it be more interesting for a cure to be available, but they need the ingredients (which could possibly involve an actual hydra - regardless, I'm trying to avoid butchering my game with an actual False Hydra), and the original Alchemist (who again, is not evil and will eventually assist the party) to create it? I would love other DM's thoughts on this. It's not too late for me to completely change this, but I think that once this one tiny tidbit gets solved, this could be a viable, albeit messed up, way of putting in a False Hydra. 

This post is also just about me telling someone about the FHSA - I have three friends who play and every single one of them are in my game, so I can't bounce ideas of anyone. I've kept this a secret only in my head for just over a year and it feels amazing to get it out.