Rayleigh has great control over advanced forms of both Armament and Conqueror's Haki. Although not as strong as an Emperor in his old age, he can hold his own against just about anyone in the series.

The fact that Sabo was considered to be the Flame Emperor, and given that he is Dragon's Number Two, fans should not be surprised to see him utilize the power of Conqueror's Haki soon enough.

Observation Haki is one of the most powerful abilities ... not everyone may possess a Future Sight as advanced as the Emperor's. This raises the question of whether this ability helped Shanks ...