I understand you, and I like the fact that you sound very motivated to do this, and I find the concept of different eras and various chapters to develop the extensive lore of the (future) series very interesting. The problem is that the project's timescale seems too big. From what I got, you are planning to release 4 games per era, there will be 5 eras, so that's 20 games. Considering the size of porn games of this genre, and assuming you will devote a good amount of your time and hard work into making this happen, it actually doesn't sound so bad and it seems doable, but that's only if you were able to release a game every 6 to 9 months. It would be a long timespan, but it still would be acceptable. However, the truth is quite different from this reality, isn't it? Because I remember seeing one of your comments saying that you are planning to release a game every year/year and a half, which makes me believe the games will be really full scoped porn games. This means that, at the earliest, you will take 20 years to finish this series, and at the latest, 30 years, and that's assuming you can consistently release a game every 1/1,5 years, without delays.
Forget those 30 years, let's just assume you "only" take 20 years to release this game. Have you ever wondered how long is 20 years? A decade is already on the long side to be following a series of porn games, but while it is generally accepted, and while there are a few series of porn game series that managed to have this much longevity and last 10 years or more, 20 years is a whole different game. There are very few, if any, series of porn games that have managed to last 20 years and are still going, at least without being rebooted, or drastically changing their gameplay and story between titles, or some other shit like that. Developers often give up, or retire, or move to other projects. I am not even mentioning the fact that I have absolutely no knowledge of any series of porn games that managed to last as long as 20 years while having the amount of content that you have planned for Succubus Covenant. One thing is true though - if you manage to accomplish finishing Succubus Covenant, you will have done something truly unique and legendary in the porn game community. And yes, as unrealistic as it sounds, I believe it's doable.
My problem is the 20 years. You are treating time very lightly when you use statements are "we are planning to release a total of 20 games, and we believe we can release a game every year, which means it will take at least 20 years to finish everything." You also have to think and understand how that timescale will affect the people who want to play your game, you and your team, and even the world around you. I will write some truths, just so you are aware of what 20 years really mean. First things first, anyone born tomorrow, or even the next year or the following year, will be old enough to legally play your game when it comes out. Teenagers who are not legally allowed to use this site will probably be married with children by the time you finish this series. Think of any of the users in this forum, any of your supporters, any of them that are 45 or over, just forget them, they likely won't be able to afford to care or won't even be around when your game comes out. As for any of your other supporters under 44 and above 18, just think about how much their lives will change in this timeframe, and try to guess if they will still be interested in your game when it comes out, or if they will still be able to find the time to play it or to enjoy it. Then let's think about the world. How will the world change in 20 years? That's a realistic danger to your project. Most notably is how much technology will change. Graphics will get better. New game engines will come out. The whole porn game community will change, the panorama will be different. Are you willing to keep your game up to date? Will you try to improve the graphics with every generation? Are you willing to get the latest version of RPGM when it comes out, or are you willing to keep all generations in MV? What will you do to keep your support alive for 20 years? People are not very patient when it comes to porn games, and no matter how much each generation will feel like a complete standalone game, they still won't be satisfied until it's fully finished. What if patreon goes down? What if f95 dies? Are you planning for unforeseen events like this, or are you only focused in developing the game? It's actually a good idea to open a website, or a blog, if you are planning on developing a game for this long. Finally, you have to think about yourself. Are you really able to keep focused on this project for 20 whole years? Well, I actually don't doubt you are. But think about it, really think about it, because 20 years is a very big chunk of your life. What if you get bored? What if you have ideas for another project? What if life just gets in the way? And about your team. Are Kaine and the other guy able to work on your project for 20 years? Are you sure they are? What if they decide to drop out?
You get the idea, right? I really, really like your confidence for this project, and it's not my purpose to spit on your idea like it's shit and take that confidence away from you, but you have to understand where I'm coming from. Right now, from a very optimistic perspective, we are looking at 20 years until you finish Succubus Covenant. But 20 years is a damn long timeframe. I just want you to understand what a timeframe that long entails. That said, 10 years, even 15 years, is an actually feasible and more attractive timeframe, and I don't think your game would be less good if it "only" took that long to make. Maybe you can still tell the story you want to tell, with the lore as extensive as you want, while making a smaller game. Maybe you can cut a chapter here and there, or maybe you can make this or the other chapter smaller, or maybe you can remove a few unnecessary details, or maybe you could do without that gameplay mechanic, and the game still wouldn't lose its quality. Just think about what I wrote, and don't just dismiss this, okay? Think about it thoroughly. Please.
De qualquer das maneiras, boa sorte, amigo. É uma estrada longa que tens pela frente e espero que tenhas sucesso na tua caminhada. Só quero que a termines a tempo.