How far does the Flowerners' connection to the Undertale's fallen humans go? Examples of this trope from a few other stories!
I think Sans pretty much confirms that the universes of Undertale and Deltarune are connected and some characters could even "migrate" from one to the other, and I believe this is what happened with the six human SOULs that UT Asgore claimed. The opened six coffins at the ending always implied some sort of ambiguity and an open end for what happened with the SOULs and it seems that Deltarune verse became their rebirth.
Flowerners have the same bullet patterns as the six fallen Human children, the same accessories and the same hobbies but yet are their own people! They do not have the same ages or even ages consistent to the order of their falling; three adults, one teenager and two children. They have very varied forms; Orange is a mouse, Blue seems to be part-butterfly and Aqua has monstrous eyes. They reference more than just the fallen humans, like how Aqua is also a bit of a Jevil and a bit of a Kris!
I think everything points out towards the fact that Undertale's fallen humans would not be just the copies of the Flowerners but all children and with human looks and colors! They carry the 'spiritual memory' of the SOULs of the humans, "genetically", but became their own people. Which would be consistent with how Toby cherishes creativity of his fans and would not crash a decade of headcanons and interpretations... but also with how Toby is a weeb and this type of birth with extremely heavy and informative "soul baggage" is a VERY Japanese trope. x)
Probably THE most popular example of this trope is from Steven Universe which, although not a Japanese media, but took very heavy inspirations from the anime. Steven is reborn from Rose's gemstone which was HER 'SOUL', her very being! However, he is neither just her reincarnation neither he is simply a child born with mother not surviving the process.
Steven is his own being, with his own personality, his own form, his own aspirations, heck with his own gender and yet he carries on a lot of traits from Rose's gemstone as a result of it also supporting his form. He carries her healing magic, he has the access to the same pocket dimension, he carries her light weapon, his fusions are same gems as what a rose quartz would give, he sometimes dreams of her memories. Does it sound very similar to what likely happened with the Flowerners?
I want to use other two examples I am very closely familiar with myself, this time from Japanese videogames; Bloodborne and Elden Ring: Nightreign! Both The Doll and Revenant, funny enough for the discussion, have their appearances actually modelled after people in the setting they are connected with; one is a Victorian mourning doll and another is... a peculiar customary gift to the house's noble lady that is a bit of a lore tangent I won't get into.
The Doll, for one, simply perceives her existence, personality and purpose as the doll, speaking of why the dolls including her are created and what they are supposed to do. There is certain "artificial" behaviour and lack of wishes and traits characteristic for humans. She is rather different from Lady Maria that her looks is based off of, however? She has Maria's voice, she has Maria's grudges, she feels same joy as Maria once have holding Maria's hair ornament, she has a strong particularity to Maria's own grave and she even can sleep and have dreams about somewhere Maria is yet!
All in all, everything points towards the fact that it is Maria's own spirit that animated The Doll. The Doll is not just Maria herself but with a bad amnesia, she is her own person... And yet, she carries a lot of Maria's spiritual baggage, simply due to being the creation of the same soul source!
Revenant is a very similar example, or even a homage as her game is the later one from the series. She became a living being on the night the family of Northerncroft, and particularly her owner Chloe, were murdered. However, for some time, she was experiencing severe disassociation remembering being Chloe herself, but soon realised her previous "life" and feelings as a doll.
Chloe's spirit herself was what animated this doll, but rather than Revenant being just her reborn she inherited some of her traits like the magic spells Chloe used to know, her sentimentality to the memo or her love for the other family members and the servants of the family. Coming to life as her own person she yet shows the traits that travelled to her being from the very reason she is alive now.
So, again: these examples all sound VERY familiar, right?
Basically... all versions of the Fallen Humans from Undertale are still valid because Flowerners are simply not "just them but with fancy colors". They somehow inherited the essence of their SOULs with corresponding traits but are their own people! The only thing we did undeniably get about Undertale's possible designs is that races and genders ARE a thing for the human kind in UTDR which used to be a debate for many years and that's it! If anything, it just helps creating more varied cast!
It feels very bittersweet, there is the familiarity that is "teasing" you with the people you used to know or wish you got to know but they did not simply return from the death. Those six Human SOULs are akin to Rose's gemstone, powering up a new person with just the hints of her own lost life slipping in.
The other bittersweet part of it is that Deltarune Asgore unwittingly caring of what became from the SOULs of the Humans he murdered in the Undertale universe feels like a strange "atonement". In Undertale Asgore took away the six humans' chances to live longer lives and get to grow up, and yet here in Deltarune he spent 20-ish years nurturing the flowers that were only meant to live for a single day. It is already heart-rending to think of how different the same person can act and the only line between the man that takes away all chances vs the man that gives second chance where it wasn't meant to be is the grief and the terrible pain that it brings.














