In my bouts of enlightenment, I kept hearing TV Tropes and too many people use the term, and even TV tropes gets it wrong too many times.
In short, Fantasy Kitchen Sink Is Modern English for The Apocalypse itself.
Which in more Modern English basically means EVERYONE GOES EXTINCT, THE END!!!
Mortal Kombat and Shin Megami Tensei(the main games and Devil Survivor at least) already get that idea very well, for crying outloud even that Manga Series ‘BASTARD!?!?!?’ got that idea right, to say nada on ‘Magic: The Gathering or Warhammer 40,000′ either.
I don’t know when everyone else gets the memo but there, I saved you 10-20+ years of Cosmic Horseshit with the fewest assumptions possible.
thesilvercross2 