A Watchful Eye
The specific definition of a “mortal” has been debated by savants over the ages, and there is still no consensus as to what it exactly means. However, it is usually defined as a one of the sentient humanoid races lacking an Exaltation.
However, this category can sometimes include those with Enlightened Essence, but in other definitions it does not.
The main factor affecting whether an individual was classed as a mortal was if they could receive a Celestial Exaltation. Generally this means human beings, but this also includes races created by the Solars during the First Age: