"Across Time and Space"

Of course, it was difficult for ordinary sacred beasts to accept the bloodline of a legendary beast. 

More often, the existing sacred beasts already had the bloodline of another Legendary beast, and they were one of the heirs chosen by that legendary beast. 

There was only a small group of sacred beasts whose bloodline wasn't from a legendary beast. 

These sacred beasts were all eager to inherit a legendary bloodline, but cultivating a legendary bloodline when they were already an adult was much more difficult than when they were still weak. 

An adult sacred beast had already formed their own strength, and when a legendary bloodline was added, it was like forcibly reconstructing a steel building. 

Many sacred beasts who got a legendary bloodline died of pain or because their body couldn't accept the reconstruction. 

It was too risky for legendary beasts to choose sacred beasts to inherit their bloodlines.