I think coming across Rantaro's body is the most shocked I've ever been by a death in a Danganronpa game.
He was so mysterious! We hadn't even learnt his talent yet! I'd assumed he would be one of the most important characters in the game, on the level of Kyoko or Hajime, his predecessors with unknown talents! And suddenly he was gone.
I was particularly unhappy about Rantaro's death because I was shipping Rantaro and Kaede pretty hard. I originally chose to spend my free time with Rantaro because he seemed really shifty and I didn't trust him at all, but Kaede's free time scenes with him were unexpectedly cute. And then, because I had the Nail Brush gift as a reward for playing the demo, I got a little scene in which Rantaro paints Kaede's nails, which was adorable. Their scenes together quickly established them as my favourite characters in the game so far.
Sorry for spending so much time with this guy and getting you attached to him just before you ended up killing him, Kaede.
I remember thinking, on my first playthrough of Danganronpa V3, that Kaede had a strangely muted reaction to finding Rantaro's body. Her quiet 'Oh, Rantaro...' makes sense to me now. She's not surprised that someone's dead; she's disappointed in Rantaro, because she thinks he's the mastermind.
I love Kaito's reaction to Rantaro's death, meanwhile. 'That dumbass! How dare he go and get himself killed? Who the hell did it? I'll friggin' punch you into orbit!' Kaito cares VERY AGGRESSIVELY about everyone.
Kaede being the culprit was unfortunately less of a surprise for me. I hadn't technically been spoiled, but I'd seen oblique references to a) people being unhappy about some sort of Kaede-related development and b) some sort of massive plot development happening in chapter one, and I put those together with my Ultimate Detective skills and concluded that Kaede might well die in chapter one. It's a shame; I'd love to know how I'd have reacted without having that suspicion put in my head!
However, I was surprised that Kaede had actually planned a murder; I'd assumed she'd accidentally caused Rantaro's death somehow by rearranging the books on the shelf! I thought the reason no one came forward to claim the First Blood Perk was that the culprit didn't know they were the culprit.
I have my live reaction to the 'Kaede actually planned this' revelation recorded in the form of the texts I exchanged with a friend:
Me: It's looking extremely probable that one half of my ship accidentally killed the other.
Me: NOPE
Me: ONE HALF OF MY SHIP DELIBERATELY KILLED THE OTHER
Friend: I'm not laughing at this but
Friend: I'm laughing at this.
Me: NOW SHE'S GOING TO BE EXECUTED AND BOTH OF MY TWO FAVOURITE CHARACTERS WILL HAVE DIED IN THE FIRST CHAPTER
Me: I'M SO UNHAPPY
Friend: This is pretty sucky
Friend: But also
Friend: THESE GAMES ALWAYS DO THIS
Me: False; my favourite characters usually start dying in chapter two.
What were the odds that my two favourite characters would die in the first chapter? One-in-eight chance that one of them would be the victim. One-in-fifteen chance that the other would have killed them. The probability that both of my favourite characters would be dead by the end of chapter one was 1 in 120. AND YET.
Even though the first case of Danganronpa V3 makes me very unhappy, I still think it's a great case. What a way to kick off the game! Given that the previous two main games had also had male protagonists, though, I do think it would have been a better twist to make Shuichi the apparent protagonist at the beginning, kill him off and have Kaede take over. (Sorry, Shuichi. I do love you! You were my favourite character in the game by the end! But it needs to be said.)
Kaede isn't thinking that they need to find the culprit in the first investigation. She's always thinking they need to find the mastermind. Replaying the case now that I understand Kaede knows she's the culprit, everything she says and thinks makes complete sense. It's extremely well done.
Anyway! Murders aside, I know what you're thinking: how would Rantaro and Kaede react if they had to stay overnight in a place that only had one bed?
No, that's definitely what you were thinking. Please don't ask questions.
My answer: Kaede's expecting Rantaro to be awkward about sharing a bed with a girl and keep a careful distance between them. He's way more casual about it than she expected, though; he's not hitting on her, but he's also not making any particular effort to avoid brushing against her, like they're friends who know each other considerably better than they actually do. She's a little flustered. She doesn't mind, exactly; she just wasn't expecting this!