Simultaneously first, biggest, and last campaign I intend to run in 5th edition of DnD. Six years of marvellous adventures in the multiverse (we did Planescape, so it was Sigil, Hades and Bytopia mostly) that taught me to hate that game as a product. I just don't want to engage with the mechanics and the system as a whole - while not particularly easy to master, it still needs constant inventions to keep things intresting.