As we all know, Blackbeard has the most powerful Paramecia being Gura Gura no Mi that has immense destructive power and the most powerful Logia being Yami Yami no Mi that has the power to nullify any effect of Devil Fruits, and has the power to maintain large gravity inside his logia.
If we go by all the theories according to which Blackbeard will get a third Devil Fruit, which should be a Zoan type fruit. Most people agree that the most powerful Zoan type fruit at this moment is Kaido’s Dragon type fruit.
Here, I’ve been going through mythical creatures and any myths regarding trinity and came across with an interesting matter. In Hinduism, there is a myth called Trimurti/Trideva, which states that there is a trinity that corresponds to Creator, Preserver, and Destroyer, which can be manifested in one single body.
So, if we link each Devil Fruit that Blackbeard has now, Gura Gura is for sure associated with Destruction only. Yami Yami no mi for sure is not creator, therefore, it must be Preserver (sustainer, nullifier). Which leaves only the Creator position, but Kaido’s Dragon Devil Fruit can hardly be related to creation.
Here, I have a better candidate for Creator position, which is Marco’s Tori Tori no mi, Model: Phoenix.