In my AU Megan is frisk, celestia is toriel, sombra is asgor, lyra is papyrus, Bonbon is sans, twilight (swi-ci) is alphys, rainbows dash is undine, vynil is nastablok, the r-dash 5000 is metaton, pinkie it’s muffet and flurry heart is asriel

A lot of people are saying Applejack shouldn’t be sans, and there are some truths about that considering sans is the most popular character of undertale and applejack is the least popular character of the mane 6 sadly. Also since sans is lazy and applejack is literally not. But I still portray AJ as sans since she’s my favorite character AND the fact that she lost her parents which she COULD secretly be depressed about. Like sans lost both of HIS parents and is definitely depressed. Soo that’s my point sorry if i offended you but YESH AJ IS SANS ^-

Some of these aren’t bad, though I object to Twilight Friskle just because she’s the default protag for everything. Switch up her and Flutters and you have something much more fitting.
 
Also I’m sorry, AJ is not Sans. The main defining trait of Sans is that he’s depressed and super tired/does very little because of it. That is the very definition of what AJ is NOT.

I would have swapped Celestia and Luna. Luna seems much more the type to ‘do what must be done’ then Celestia, and we know Celestia has a habit of taking children under her wing. Other than that, this if frikin spot on!

@Dr_Osaka  
Given that Asgore and Toriel were once married and ruled the monsters together? No, one of the alicorn sisters or Cadence works better as Toriel, who’s never been the shy type; reserved, yes, but not shy or afraid to speak her mind. As far as personality goes, Alphys is a much better match for Fluttershy.
 
Also, Trixie as Papyrus? That’s not a very good match at all. The one and only thing those two have in common is their tendency to refer to themselves as ‘Great’.

I always saw Celestia as Toriel. The way she is speaking sometimes reminds me more of Toriel (or Momlestia^^)

Well I do agree with Rarity as Mettaton and Rainbow Dash as Undyne; Discord as Flowey is just hilarious.  
I think Fluttershy works as Toriel better and Pinkie should completely be Sans while Trixie should be Papyrus. Frisk could be any of the CMC as I feel they fit a bit more then Twilight (who could maybe be Dr. Alphys). And I suppose Celestia could be Asgore, either her or King Sombra I suppose

@omnimon11  
Then again, Chrysalis and her Changelings could take on the roles of Muffet and her spiders…
 
And, also, since Moondancer and Twilight look alike, Moondancer could be Chara.
 
Tried editing my previous comment but it seems there’s a bug that preventing that.

AppleSans, Flowercord, Alpshy, Pinkie Pyrus, Queen Celesgore, Princess Luniel, Rainbow Dyne, Rariton, and Twisk.
 
Why not have Chrysalis and Cadence be Flowey and Asriel respectively?

@thereallegend123  
Well yeah. Self-conscious otaku lizard fits better with yellowquiet, and if bluefast is Undyne, then Scootaloo becomes the most obvious choice for her adoring fan. Almost everyone is going to match up the royalty with the princesses, it’s just a matter of which one you think makes more sense for which.
 
Best choice of those is probably hOI! I’m PINKIE!!!!

I searched “Undertale” on Derpibooru tonight thinking, If I don’t see an image featuring Twilight as Alphys, Rainbow Dash as Undyne, Pinkie Pie as Temmie, Rarity as Mettaton, Fluttershy as Shyren, Applejack as Toriel, and Spike as Monster Kid, I am going to be disappointed. Things aren’t looking so good.

@angrybrony
 
Dangerous =/= Evil
 
She was nuts, and pretty strong, but not what one would call evil.

@Background Pony #E5DF  
Wouldn’t is still be Discord? I mean, it makes no sense given how Discord acts, but considering who Flowery is…
 
:/ Maybe Silver Spoon? Starlight Glimmer?

wait if Discord is Flowey…Then who’s Asriel?

@Mugen Kagemaru  
Hm… I’d be okay with this, given the context.

@Mugen Kagemaru  
yeah but starlight was way more evil than sunset.

@angrybrony  
Except Starlight came after Twilight.
 
It would be like if someone else fell down into the Underground after Frisk’s adventure.

@Mugen Kagemaru  
starlight would fit better.

Sunset as Chara

Celestia is the most motherly one the Royal Sisters, a mentor and teacher figure, seeing her subjects as her children or ‘my little ponies’.
 
She would make a much more fitting Torial then Luna! I could better seeing Luna taking up the case of war against humans, more quick to fight… For her older sister Celedtia to chide her in the end and stop the fight between her and the human.
 
I always felt Luna was the one with more of a temper, the one more likely to be rash and start a war. To grow angry at the misdeeds of humans… To later regret such a choice but continue on the path anyway.

Characters as follows  
Asgore:Celestia  
Toriel:Luna  
Undyne:Rainbowdash  
Alphys:Fluttershy  
Sans:Pinkie  
Papyrus:Trixie  
Flowey||/Asriel:Of course it’s Twilight.||  
Frisk and Chara Remain as they are You could make chara a human sunset but chara is a more detailed character than sunset
 
Not sure why everyones always saying frisk should be X character, the whole point is that theyre an outsider.

@EquestrianScholar  
Wrong. Celestia is the one who stayed behind to rule her subjects. Celestia is the one full of grief for what she must do. (even if it twilight ended up saving Luna for her). Celestia is the one who loves her sister, and Luna is the one who holds a grudge.

Applejack: y’all gonna get a bad time, sugarcube.

I think I agree with this casting in its entirety. I love this picture, but unfortunately it’s just a little bit eaten up by JPG artifacts.

Sans and papyrus should be pinkie pie and rainbow dash…. :P  
Well.. uh.. Rainbow could still be undyne but, pinkie would match sans better when including the jokes.. But GOOD PICTURE STILL!! :D  
Tells you that this is just a suggestion  
:3