[ He is his...

Something aches in his chest when he hears that, unsure of how to process that bit of information outside of just... hugging Byleth with joy. He was already hurting at the thought that Byleth had changed his mind, that he didn't want him or didn't see anything worth staying with any longer. And he honestly would not have blamed him either, especially after what he'd put everyone through.

Hearing that reaffirmation only makes him hold him close again, though—

What he hears next makes him look at him in surprise. ]

Rhea... is Seiros?

[ Did he hear that right? And the Ten Elites, the bearers of the crests that they all inherited.. what does that make them? He looks a bit lost as he stares at Byleth, unsure of what to think right now. ]

... Byleth— before I speak to her, if she's even willing to speak to me... what does this mean for us? For you and myself? If what you're saying is true, then haven't I been among those that have done you all wrong?

[ He's not even questioning it, Byleth has no reason to lie to him. He just wants to know what this means. ]