I just noticed that the FTW/Zenith Seed not only have their name on master, but it also shuffles up the previous names too, that's pretty neat:
I played Zenith on Expert Mode, so that became Master, so technically I've defeated the Zenith Seed on Master Mode then.
I played Zenith on Expert Mode, so that became Master, so technically I've defeated the Zenith Seed on Master Mode then.