Was struck with nostalgia this evening, about how there used to be all sorts of theories and fanworks about the Riverperson’s true identity and connection with Gaster in the early Undertale fandom says, but they’ve died down a lot in the ensuing years.
Then I had a minor realization. I know a couple of people have pointed out the similarities between Riverperson’s sprite, and the hooded cloak Ralsei has on for his first appearance and when the prophecy first shows the three heroes. But there are a few other similarities, too—
The biggest one being, Riverperson’s most famous for going ‘tralala’ in their lines, and sometimes even inviting Frisk to sing with them… and you know what Ralsei does when ACTing? *He sings.* Not to mention, it’s clear that both Ralsei and the Riverperson have far more knowledge about their circumstances than they easily let on—Ralsei for obvious reasons, Riverperson for strange lines ‘Beware the man who speaks in hands’ ‘Beware the man who comes from the other world’ and ‘Humans, monsters… flowers’ ‘The angel is coming,’ as well as mentioning ‘the old song from the sea’ and foreshadowing how to spare numerous monsters (something Ralsei would have a vested interest in…)
So… do I seriously think that Riverperson is Undertale!Ralsei, or Deltarune!Ralsei transported to Undertale? Not really. It’s maybe something to consider, but without the other Darkners present in any form in Undertale, it raises a lot of questions about Ralsei’s existence or being paralleled—tho, Ralsei has always been pretty odd for a Darkner.
I’ll just cap this off with one thing. If Riverperson is Ralsei, and especially if Ralsei is some kind of shapeshifter like I’ve seem theorized, and if River!Ralsei has any awareness of the similarities between Frisk and Kris… it just makes some of Riverperson’s lines downright tragic.
“Tralala. I am the Riverman. Or am I the Riverwoman…? It doesn’t really matter.”
“Tralala. What’s my name? …It doesn’t really matter.”
Ah, this is fascinating! I've seen people compare the two as a joke, but this is the first real time I think I've seen a serious analysis done, and I must say you come up with some compelling points! Both of them being introduced wearing cloaks and acting as guides of sorts definitely ties them together a lot more strongly than perhaps any other character in either game.
This point is particularly interesting when you consider their identities - or rather, their lack of any. I strongly believe that Ralsei was never meant to take the cloak off, and would have floated through the game without really connecting with Kris or Susie or anyone else, or developing an identity of his own outside of "useful healing tutorial fairy person". Meanwhile, Riverperson has no identity at all aside from their profession as ferryman - even their gender isn't explicitly stated anywhere, as far as I know! You could definitely see Ralsei in this light as being a commentary on "tutorial/exposition characters" whose sole role is to assist the player in some way and nothing else, where this kind of character is instead allowed to grow, be challenged by the narrative and flourish into their own person.
I suppose that would retroactively make Riverperson a commentary on characters who know vastly more than they should being relagated to a bit role with no importance whatsoever. Of course, those glimpses of meta knowledge compel us to ask questions about them - who are they? How did they come across that knowledge? And as if anticipating our questions, Riverperson shrugs them off, proclaiming that their name and their gender, and by extension the rest of their identity "doesn't really matter".
Actually, I'm curious now - does Riverperson have any fans? Anyone make fanart of Riverperson, or write fics about them? I suppose no-one would, really, considering their lack of importance and lack of anything concrete to latch onto. That certainly resonates with what Ralsei's trying to do with himself, attempting to minimise his own importance so that when Kris and Susie have to move on it won't hurt as much. Hmmm...
You've given me a lot to consider here, thank you for the thought-provoking ask!