Modern - Strobe Kiln Fiend (Modern)

This is arguably one of the fastest decks possible in the Modern format because you can win on turn 1 as player 1.

The probability of that happening is very low, but it is none the less possible with the right combination of cards , which are:

1. mountain + 2. kiln fiend + 3. simian spirit guide + 4. simian spirit guide + 5. simian spirit guide + 6. reckless charge + 7. assault strobe.
   (This has changed since the last update with pyretic rituals included)

This "Kiln Fiend" and "Assault Strobe" deck is built to be fast, but it's very fragile to disruption and can easily lose to control decks, but it is very likely to win matchups with decks that are trying to do a combo of their own without disrupting their opponent, as the kiln fiend deck is just too fast when the all the pieces fall in place. Getting a winning attack going on turn 2, turn 3 or turn 4 is quite likely. (e.g. play Kiln fiend on turn 1 with Simian spirit guide - opponent does nothing to remove it nor plays a blocker - and assault strobe + reckless charge for a 10/2 double strike attack). Adding a couple of pyretic ritual, or replacing the simian spirit guide with them, would presumably alter the performance profile of the deck - e.g. make turn 1 win a bit more likely as it would work with a combination of 1 simian spirit guide + pyretic ritual OR simian spirit guide + pyretic ritual OR simian spirit guide, but it would not have that much effect on winning on turn 2, because the easiest way for that is to play a kiln fiend with simian spirit guide on turn 1 (pyretic ritual can't be cast on turn 1 without simian spirit guide) and then just play reckless charge + assault strobe or some combination of assault strobe and mutagenic growth , crash through , slaughter pact etc. With these cards the prowess mechanic utilizing monastery swiftspear and soul-scar mage can also deliver a winning attack.