P.S. its funny how many martial arts have stories of how their originator decimated all the opponents in other martial arts.
To me success in real situations is far more dependent on your attitude and natural fighting ability, learning techniques is just a bonus and allows you to act instinctively instead of freezing - don't ever believe there is an ultimate martial art of ultimate martial artist! In fact every situation is different and I'm sure you could kill any martial artist given the right conditions (e.g. enough suprise).
[this may exclude Ueshiba if you believe he could actually see the spirit of the attack before it began - which I reserve judgement on]