This was a really cool and unique playthrough! I really love the character designs, and you can absolutely tell how fleshed out this world is, so your worldbuilding is on point!
I did want to point out something I found: because most of the combat revolves around picking a larger number than the opponent, you can actually just brute force all the battles by always picking the biggest number and not even paying attention to the equations. It might benefit to have some subtraction, or some kind of rule that prevents players from just mashing through the combat, because you have something really interesting here!
Also just wanted to add that, although your characters and lore are really interesting, the ratio of cutscene to gameplay is pretty heavy on the cutscene side. You might wanna even it out a bit cause I found myself kinda glazing over the dialogue after a while because it went on a bit longer than I was expecting.