According to his experience, not only is the cultivation of the fourth mortal coil the minimum requirement to learn the vessel sigil techniques, but it is only the geniuses that will manage to learn them and activate them at the fourth mortal coil.
It is those geniuses who have a good chance of successfully advancing to the fifth mortal coil. Of the total of 28 golden core cultivators in the sect that he is aware of, only four of them have learned one of the vessel sigil techniques.
Of these four, he knows two of them. These two are Pink Ivy and Void Claw. They are also the only two golden core cultivators in the sect other than him that forged a perfect core.
He doesn't know the identity of the other two that have learned the vessel sigil techniques, but he knows for sure that only these four have learned the vessel sigil techniques because once one is capable of activating them, a permanent mark and sigil will appear on their forehead.
