After defeating Vyraz, and after the cutscene, Draka and Thrall will have this brief exchange before walking through the portal.
Draka: Well fought... Go'el. Come, we will speak.
Thrall: You... knew?
On returning to Korthia, you will have the option, on reporting to Draka, to give the two a moment, after which, the following dialogue plays out.
Draka: I knew who you were the moment I saw you. Do you really think I would not recognize Durotan's eyes? You were but a babe when I died. Tell me, who have you grown to be?
Thrall: I was once Warchief of the Horde, a shaman of the Earthen Ring--
Draka: That is who you were. Who are you now?
Thrall: I am... uncertain. Much has happened in my life. I do not know where it will lead next.
Draka: A lesson, then. Not from mother to child, but from one similar soul to another. Remember who you were, but take pride in who you are. I once thought death was the end. But now, as a warrior of Maldraxxus, I see that it was only the beginning. It brings me joy to see how far you have come. And I know you have much farther to go.
Thrall: Thank you... mother. I will make you proud.
Draka: Come. I wish to know more of your life. All of it.
They remain by the fire after that, and say nothing else. Though very understated, I think it's a nice moment. I don't play Horde, nor am I a huge fan of Thrall (like many, I got "Green Jesus fatigue" back in Cataclysm), but even so, I spent the entirety of the preceding quests wondering when the shoe would drop. Bittersweet, but very touching.