If someone asks, every dialogues happened in Arc 4. So beware of spoiler.
"Yeah, power to redo the world is incredible, doesn't it? Messing with time is barely possible only with the ultimate shadow magic. Even Beatrice could make time stand still at best. Reversing time is dream within a dream."
"Because of you, even a powerless half-elf could aim for the throne. No, she will be the king. You will prevent any other possibility from happening, and finally grant her wish. You just got that kind of power. If Emilia-sama has ANY value, it is having you as ally."
Roswaal's view on 'Return by Death'
"Your ability, 'Return by Death' is amazing one. You don't understand how useful it is. Repeating the world as much as you want is ultimate dream for the researcher. Because no research could be done in the exact same condition (skip) Returning to the point, I am really envious of your ability. But what waits you ahead is really hard to overcome. I respect your resolve to solve them all on your own, and very miserable to see. But I think it is better to know everything no matter how it seems miserable. Any future, even when you lost all feeling about everything from repeating death, is better than the future without you (skip)"
Echidna's view on 'Return by Death'
It is actually just a part of incredibly long line(total 4729 words) explaining why Subaru should make a contract with her.
