Souls

Souls (or Spirits), are celestial beings made out of pure energy, and are linked directly to the soul of Kronos, making them immortal. Although, a powerful enough Magi with a vast supply of Runes could break this link.

Physical uses of Souls
Some magic users who have recieved extensive training can tap into the power of souls, and feed off their energy as if one were stealing the power of Kronos.

Another use is to trap a soul in a body, thus raising a perfect replica of a living being. Soul Energy can also be drained and trapped inside a body, thus creating a semi-sentient being capable of somewhat little.

Souls are invisible to the human eye, unless a powerful spell is used or the soul wants itself to be seen. Thus, spirits can appear in any manifestation they want, but usually appear as some sort of bird.

Through intense meditation, one can increase the power of the link between soul and body, thus increasing ones lifespan and physical capacity for magic.