Young Master Tatsuya
Life. It was a short four-letter word, but it encompassed a level of depth and mystery that could hardly be fathomed. There wasn't an individual in existence that could, with any sort of certainty, claim to comprehend it in its entirety.
However, if one wanted to start peeling back its layers of complexity, how would you begin? Would you start with a list of species? Maybe you would start by defining what it was you considered life to be? Was it a word that referred to those that lived and breathed? Or was it more enigmatic, taking all of existence under its wing?
If the few wielders of the first ranked Heavenly Pupils were to be asked such a question, they'd answer very simply. To them, there was no confusion at all. Life. It was a complex realm of cause and effect. Nothing more, nothing less.