"Yes." There was something in Zero's normally flat, stern eyes that brightened at the mention of X, like a spark was lit behind them. There was a fondness that he didn't show to most people, and pride mixed with melancholy. X had been someone special. Irreplaceable.

Maybe it was the fact that Hajime had already peeked into such an intimate moment between the two reploids, but Zero began to explain, "He's been my best friend since the beginning. Through two wars and the near destruction of earth... we fought, side by side."