Grey wasn't too interested in what the others thought, but he realized something when he did this, he had absorbed the blood essence of a Dragon, one of the top bloodlines in the Magical Beast world. Originally, he didn't think too much about it, but now that he studied his blood more intently, he realized it was no longer as it used to be.
To a certain extent, it has changed completely from that of a human. He rarely bleeds when fighting, and even on the few occasions he does, his bleeding stops very quickly, and due to the intensity of those battles, he doesn't even have the time to notice the changes in his blood.
But now that he was the one who actively cut himself open and extracted some blood, he realized his blood was not like anything else.
He had eaten a good number of Magical Beasts, and those had in some way integrated themselves into his blood. There have been a few high bloodline Magical Beasts he has eaten which has also helped him out in this.
