User blog comment:Xilinoc/Ch. 565 (Mangapanda is run by lazy barnacles)/@comment-24282510-20140123205815/@comment-11051098-20140124161733

Ôetsu Nimaiya confirmed that the appearance of "old man Zangetsu" was Yhwach from 1000 years ago. In relation to that, I'd say this chapter basically confirms that the appearance of Tensa Zangetsu is Yhwach when he was young.