Cain was judged by the other gods, and they discovered that he possessed an immortal and indestructible body. No one could do anything to him. Here, the immortality is likely due to the effects of this "Blood Rhythm" Divine Power.
Therefore, the upper limit of "Blood Rhythm" is quite high; it's just that it's normally applicable in rather narrow circumstances.
The other "existence" is one of the Royal Family's rare Blood Rhythms, capable of instantly changing one's presence, a divine skill for escape and assassination. Although it is not a combat Blood Rhythm, its practicality isn't bad.
Apart from generation and Blood Rhythm, what's left is the enhancements to Divine Power, God's Defense, true HP, and HP recovery speed.
Mu You glanced over his current panel.
[Generation: 7th.]
[Divine Power: 4 points.]
[God's Defense: 4 points.]
[True HP: 130 points.]
[HP Recovery Speed: 8 points per second + 1% of maximum HP.]
[Blood Rhythm Points: 9 points.]