As an immortal, just one strand of immortal qi is extremely valuable to the point that an immortal will kill just to have it.
One's strength as an immortal is determined based on their immortal qi. It is what they depend on, just like how Spirit Kings depend on spiritual qi.
Of course, that doesn't mean immortals don't use spiritual qi. They do depend on it; however, in a battle where the opponent is using immortal qi, using spiritual qi against them is akin to courting death.
So, immortal qi is extremely important.
Of course, there are three ways of obtaining immortal qi.
The first is the basic, which is as simple as refining spiritual qi into immortal qi. It may sound easy; however, refining spiritual qi into immortal qi is extremely difficult.
In fact, it is borderline impossible to achieve that.
One would have to spend thousands of years in seclusion just to refine one strand of immortal qi.
