Dota 2 is about to change thanks to the new 'Rekindling Soul' update, which should be available right now. Along with all the promised 6.82 balance updates comes the new, metamorphosised Shadow Fiend. Not only does the fiend look different, but the update also introduces the Demon Eater Arcana variation, which turns the Shadow Fiend into a whole different beast. If you buy the Demon Eater set before October 31 you'll get the 'Exalted' quality.
That's only the tip of the iceberg, and if you're a Dota 2 player you'll probably want to pore over the thoroughly detailed update notes over here . For everyone else it's good enough to know that pretty much every aspect of the game has been tweaked to some degree, from the abilties of certain characters through to the layout of the world itself. That latter point is interesting, since it's the first layout change for years.
Full patch notes are on the Dota 2 website .