Source of the asetian immortality

Is the vibration and nature of the asetian soul their source of the imortality or their culture and knowledge wich keeps the flame alive or could be a duality of both ?

The source of immortality within the Asetian soul does not come from their knowledge or wisdom but from the Violet Flame which is the essence of Aset.

In addition to this, I would say that the vibration of the soul is caused by the Violet Flame. Their culture and knowledge do not cause that immortality but instead stem directly from that. Since their vibrations are so high and their essence is not native to the physical realm, this leads to the well-known facet of vampirism. It is through vampiric practices that they can increase their personal alchemy and reach further with more magickal potency.

The Asetian culture is a beautiful thing. It brings initiatory lessons about the universe and the nature of magick. Their culture carries the banners of a time that mankind has now forgotten in its ignorance. It is definitely a celebration of honor, wisdom, and transcendence.
Keeping the "flame alive" also ties in with vampirism. It ignites spiritual potential and fuels magick, being practiced by various souls other than the Asetians as well since it can be a potent tool.

Wisdom and spiritual growth are important but can never gift immortality since that is tied to an ancient and secretive process, well-guarded as it always will be.