One thing that puzzles me the most is that in the Reverie arc, he seems to be aware that the Warlords were going to be abolished before the actual declaration was made. He was staring from the windows as if he was looking through Mariejois. Maybe his clairvoyant ability is like to Viola's devil fruit.
It reminds me of how Shanks was able to tell Greenbull was in Wano at great distance.