Lots of people especially after the recent manga developments think that Aokiji (Kuzan) is the Tenth Titanic Captain. I don’t think he is.
The Ten Titanic Captains were already introduced during the Dressrosa Arc, when Aokiji still had to join and Burgess didn’t like the prospect.
I don’t think the 10th Titanic Captain is Stronger, the horse ridden by Doc Q. It wouldn’t make any sense, otherwise why would there be such mystery about it. We have Road to Laugh Tale chapters, which were post Wano raid, where the 10th Titanic Captain was still hidden:
This means the 10th Titanic Captain is someone who had already joined the Blackbeard Pirates crew during the Timeskip. And I think the Tenth Titanic Captain is Urouge “The Mad Monk”.
In the aftermath of the Paramount War at Marineford, Urouge said that Blackbeard is the key of the New Era, and the man who will rule the seas in the next decades. Sounds like the words of someone who would be willing to be his underling.
Kuzan definitely joined the Blackbeard Pirates after Urouge, and not as a mere ally, but officially as a Titanic Captain, in fact you can see it in the recent cover story “Auger and Kuzan of the Blackbeard Pirates” which means he definitely joined as a member of Blackbeard’s crew.
We also saw Moria going at Fullalead to retrieve Absalom and getting cornered by Shiryu and Devon, Blackbeard asked him to join the crew, and we never saw what happened after it. My guess is that Moria couldn’t escape and didn’t have a choice, if he refused to join, he would have been killed, so he actually joined the crew as the 12th Titanic Captain after Urouge and Aokiji.
His powers could also be very useful for Blackbeard to retrieve powerful shadows in powerful corpses, for example we know that at Thriller Bark he had Ryuma and Captain John’s corpses. And we don’t even know what he could do if he awakens his Shadow Fruit.
So to sum up, I think Urouge is the 10h Titanic Captain, not Aokiji. In order of who joined first, it’s like this:
Tenth Titanic Captain: Urouge
Eleventh Titanic Captain: Kuzan (Aokiji)
Twelfth Titanic Captain: Moria
So I think there are actually Twelve Titanic Captains right now.
*Theory by West_Conclusion_1239