Conditional Immortality.

His race has changed from a giant of order to a sun giant. His body upgraded from half-divine which demigods possess to half-celestial which only a few possesses. That's why his race changed. He used to be a pretender before. Now he is truly the son of the sun god. They are joined now in more than just divine power. Helios has gained access to his Authority. It is much more powerful than divine power.

Transcendence means breaking your limits. The process is dangerous but it is highly rewarding. You are rewarded with evolution and the power that comes with it when you combine the potential of your soul and your body to break the limit on each of them. Individually, a being can only reach a stat of 1000 at any point without external Influence. It is called the mana limit.