"Who is in the Imperial Palace right now,..." "...who could have done this?" "Ivona Vouten!"
Or:
"Right now in the Imperial Palace,..." "...there is only one, who could do this." "Ivona Vouten!"
"Can I ... live like that?"
-> "Can I ... also live like that?"
"Thank you for letting me know where you are"
-> "Thank you for letting me know about this."
Or: "Thank you for letting me know about this situation."
"Can I keep your help a secret?" (Because I want to take all the credits alone.)
-> It's either: "Can you keep my help a secret?" Or: "Should I keep your help a secret?"
The answer would then be either, "Yes!" "Of course!", or "Yes,..." "thank you."
Also that part about, "Mana must be used by the magician" "Is it true that only a bit is used by the summoned spirits?!" must be ironed out somehow, as I didn't get, what they wanted to talk about. And as I didn't get it, I also have no suggestion.
"What...when are you going to grow up?" "Will you go to the wedding ceremony alone, too?"
-> "What!? ...You Child! When are you going to grow up?" "Do you also intend to go to your wedding ceremony all alone, too?"
"If I never were in your life-" "Please forget me."
-> "Please forget about me-" "as if I never have been part of your life."
The last two are simply puffed up a bit to add a extra scoop of drama to them.
As a non-native english speaker, that's what I would have expected to read. Please point out any mistakes I've made.