For his Desperation F he loses 2 vitality after each attack resolves. Lets say during the damage step the opposing player takes enough damage to "die". However, Ragnar will also lose his last 2 vitality after his attack resolves. What occurs first? Is it simultaneous? Double K.O. Yea or Nay?

attack deals damage before ragnar does is the short answer.

Ragnar wins.

To clarify, the damage step comes before the attack resolves. Keep in mind the damage step is followed by the reversal step, for one...