This chapter also confirms that Blackbeard is a strong armament user with massive physical strength
> He could block a mountain slicing slash with armament alone, and cutting attacks bypass armament better than blunt if the haki isn't strong enough
> Furthermore, when he held Hancock by the neck, she couldn't do anything to get away, showing that her physical strength was no match to his
And he also showed the ability to use observation haki preskip when he could sense Luffy's haki in Jaya and even evaluated it's growth back in Impel Down
No wonder then that he was mentioned to be commander level even without his devil fruit.
And it shows as well just how much underrated the Ace vs Teach battle was. No wonder their battle was threatening an entire island