Ok so - I had all the items needed to become king - and had done it correctly, however the guards kept kicking me out, and when trying to enter the goblin cave I was kicked out from there as well, and being forced into a loop with Gwynn where she tells me to go make plans with Nyx to have her pretend to be a slave and me pretend to be a slaver. So the issue here is the quest is actually not active - and there is no option to get Nyx to execute the plan. I kept trying, and I kept trying to mess with different stuff in the saves - though I'm - as I said - a n00b - so nothing really helped my issues.First of all respect getting the scepter without the potion. Never thought that would be possible, so I may have forgotten to account for that in the quest dependencies.
If you have the goblin crown (you get it when conquering the very last field) and the scepter, access to the keep should be possible.
So after getting the crown, chat to Gwynn, if Irith is back at the keep already and cured gwynn will kick off the goblin crown quest. Once this is done, having the scepter in your possession should activate the "make yourself king" quest regardless.
If that does not work, something might be broken and you'l miss out on the better part of the animations & cutscenes. In that case: New Game -> Start with Act 5a should put you about where you are now and you can complete the game with a consistent state.
One afterthought: I think i fixed the out of order Scepter retrieval in V0,9c, so your game state might be V0,9b. Not fully sure how thats factoring into the inconsistencies. Anyway, as backup you can always use the Act5a option.
So what I did was that I went back to a savegame just before taking the last tile on the gate map - and did everything I had done before except getting the scepter "early" - and everything worked as intended. So I guess that'll teach me to abandon my old "adventure game ways" of trying to figure stuff out without looking at the guides as a challenge - and just do it the modern way with just following the guide step by step! (Half joking btw. But that in essence what got me in this mess and why I tried to figure it out for like 15 hours! LOL)
Thanks for the entertainment though! I wish the game had a "darker/more evil" path and maybe a "heroic" path so your decision felt like they had greater impact - but it was a fun experience as it is - except for all the trying to figure out code in a language I don't know! hahahaha
Also while I'm giving input without you asking for it - why not make a "queen" path where it has 2 branches.
1: where you help the Queen with the promise of rewards where you somehow get something from her which ensures that she can't screw you over - and you stick with the plan and help her.
2: where you do the same thing up to a point - but then use that "something" to enslave her and become an evil version of the king path.
Just ideas for inspiration to make the game feel more like your decisions matter.