何々だと言うのか?!

I was wondering whether there's a literal translation that could include the meaning of "だという", rather than just translating it into a question. All I can think of is some kind of emphasis, but I'm not sure how I would include it in a translation.

Ex:
Setsuna:
あれが…
That's...

Frame 2:
Setsuna:
殺生石の妖力から解放された
after being released from Sesshouseki's Youryoku

Frame 3:
Setsuna:
白叡の…
Byakuei's
真の姿だというのか!?
true form?!