The ego comes from the Freudian structure of the psyche. All you people freaking out about having its back broken can rest assured that you still have an id and a superego in this analogy. Who needs an ego when you have a SUPERego heroically waiting in the wings to fly in and take over?

From what I could gather from the OP's comments, the idea of breaking the controlling power of the part of your mind that purely seeks to gratify the id is another way of explaining masakatsu-agatsu (true victory being victory over the self). The will of the Freudian "ego" attaches you to the mere vehicle of the mind (i.e.: the body). This isn't airy fairy spiritualism- it is the cultivation of a mind that manoeuvres that vehicle in a better way. It is being not less of a person but rather it is the idea of elevating yourself to be the best person you can be.

(…reaches for another beer…)