attacking with flesh reaver and both players lethal

[Swamp]

If I attack with a Flesh Reaver and I do lethal damage to opponent but flesh reaver does also lethal damage to me, what happens?

[kinda]

I think if both players die at the same time its a draw

[Kenji]

Right -- if both players actually went to 0 life at the same time.

However, that is not the case here. Flesh Reaver has a triggered ability which goes on the stack, and has to resolve before it actually deals damage to its controller.

If your Flesh Reaver attacks an opponent who has 4 or less life, the damage has to actually be dealt to your opponent for Flesh Reaver's ability to actually trigger. Of course, once it does trigger, your opponent loses the game for having 0 life as a state-based action. This happens before the triggered ability of Flesh Reaver even goes on the stack. If you were playing a two-player game, then obviously the game is over, and the ability won't ever be added to the stack. The fact that your life would go to 0 if the ability resolved is irrelevant, since the ability won't even be on the stack before your opponent loses the game.

Do keep in mind that in a multiplayer game with other opponents remaining, the Flesh Reaver's ability will go on the stack and resolve, and will cause you to lose the game if you end up with 0 or less life after it resolves.