What ironic observation does gene make while watching the troops and war machinery assemble on Devon's campus? What does he probably mean by it ?

Gene says he has already killed his own enemy, and therefore has gotten rid of his hate and his fear. Gene's enemy must have been himself, or at least the part of himself that was so quick to lash out and hurt other people. He believes that he has buried his darker side, and from what the reader can tell, maybe he has.