Why Did I Feel Like I just Finished A Tutorial?!!

Zen.

  Mysterious natural soul energy that could only be manipulated by someone who was already reaching at least, a demigod level.

As a mortal soul(Ordinary) being tempered continuously by using magic or elemental energy( Which was basically level up), little by little it will start growing stronger before it solidified and started evolving to be an independent high-quality energy resource.

By nature, all the living being in the universe has a soul power since birth.

However, before it could be used as a very powerful independent energy, a process was needed to temper it from a fragile state( when they were just born) to a solid-state( Crystalize when they reach a certain rank, in a common case a Grandmaster level).