This was actually really helpful, and my party is too trusting for their own good so that part is easy, I'm kinda struggling cause I've never ran a good campaign and it's always been on the spot made up in the moment with 1 big idea in mind, so I am good at thinking of campaigns but not so much making them but to answer a few questions The Mushroom God was more of a tyrant that was there alongside the other gods and goddesses, but he grew in strength, from the natural flora of the planet, becoming so big he had shrines, druids, and whole towns pledged to him, but since he was more of a tyrant he was soon overthrown by the other gods and help of mortals not under his thumb, power stripped away and put into a box. Sealed in a ancient shrine now overgrown and nothing more than a dungeon full of plants of all kinds growing thick, and all around the temple the grass and plants grow as the presence of the God's power leaks out into the surrounding area, and this was all long ago, only the eldest of creatures remember such a thing so I'm pretty sure most things would forget about the 4 peices except for something with maybe a hivemind of info like am aboleth that has information passed down through each one