@Ereiam  
She ended up captured by his hive years ago, and he decided to help her escape, but because she didn’t trust her captors, he had to disguise himself as Cranky until he got outed and they grew to trust each other from there.
 
Is it true? Hell no, I just came up with that in two minutes. But it’d be cool.

@TheMasterEraser  
Kevin is actually acquainted with Matilda (according to M.A. Larson on Twitter). No idea how they met however.

@KrautalicornSS  
I thought us fans named him during the airing / livestream, the show staff agreed, and then it was put in the card game?
 
It’s funny because it’s normal.
 
I wonder how Cranky met him?

@Scribblepwn3  
I see where you would get that idea.

It’d be cool if they explained this other changeling from Slice of life. They likely won’t though. Perhaps it’s from a different hive? Slightly different colours.

@Data Expunged  
I explained the difference between the two’s colors on the bottom of my comment.

@Smudge_Proof  
Like I said, I’m color blind.

@Smudge_Proof  
You made a small typo, it being black instead of back.

@Sgtnolisten  
Kevin was named by the creators of the official card game on the advice of M.A. Larson. For once, we are not to blame. Though I have to admit I’ve kind of grown fond of the name. It’s so generic for us, yet to ponies, it must sound rather unusual.

@Data Expunged
 
Yo listen up here’s a story  
About a little guy that lives in a blue world  
And all day and all night and everything he sees Is just blue  
Like him inside and outside  
Blue his house with a blue little window  
And a blue Corvette  
And everything is blue for him  
_{I’m the lowest of the low. Sorry!}
 
Thorax’s eyes and black are green. Kevin’s is blue.

All I see that is different is that Kevin’s exoskeleton on its back is a darker blue and his eyes are ever so slightly a darker blue as well. DON’T YELL AT ME IF I’M WRONG WITH COLORS! I’M COLOR BLIND!

@Background Pony #2AE7  
I think it’s all just because he, his wife, and the princesses were all up at the front and… Kevin (really you guys? Really? All the creative names we’ve come up with over the years and you give the first non hostile changeling we’ve seen in the show the name “Kevin”?) was all the way in the back.
 
Which also ties in with the “Ponyville is used to seeing weird crap” idea. While they’re hesitant with a undisguised changeling as evidenced by the foals trying to sit as far away as possible, none of them really felt the need to point out the changeling.

@Background Pony #73A6  
Even the shape of the eyes, too.

I tend to take anything that happened in “Slice of Life” to be of questionable canon relative to the rest of the show, since that episode was focused on the background ponies and their problems instead of on the mane characters. So a changeling showing up at Cranky and Matilda’s wedding really doesn’t affect the overall story line that includes changelings being (as far as ponies know) a uniformly evil menace.

@Background Pony #65C3  
That is most likely what happened. Pony is definitely not scare-proof either like other people are saying, and at least three members of the town have ill thoughts towards the changelings, seeing how they were used by their Queen against their will.

People always assume that Kevin is Cranky’s guest at the wedding, when Larson explicitly stated that he’s a friend of Matilda’s. Which makes sense, sice he was sitting on her side of the aisle. Along with Celestia and Luna.
 
Just who is Matilda?

Well, to be fair, “Slice of Life” happened before the baby was born…

The real question is why Doomie was renamed Kevin.

@Background Pony #65C3  
Fair enough, didn’t know about the deleted scene. Is it available somewhere?

actually,Kevin and Thorax Are Twins.

Tail and eye color, even the shell on the back.

Starlight was not present at the wedding which really starts to make the theory fall through. It is justifiable that Starlight would avoid taking part in the Zombie Prank because she probably doesn’t care about silly stuff like that and/or RD never pranked her because she was still a bit wary of her.
 
But that wedding had pretty much all of Ponyville present. And Starlight was absent from the Bugbear fight even she would’ve been a great help in beating her up.
 
I think Kevin must’ve snuck in without anyone but the foals noticing, and then snuck out before anyone realized. He was just there to eat at the buffet after all. One of the deleted scenes was at the end a whole swarm of Changelings were going to be seen flying towards the city hall.

Kevin, Cranky and Steven Magnet bonded over the many adventures down the road proving himself worthy of coming into the wedding as a old friend.
 
Thorax is a freshman at this friendship stuff.

@Background Pony #3292  
I think he was treating it as a general risk to the kingdom.
 
@FanOfMostEverything  
True, but the adults seemed chill, so it must have been okay by them.

The show’s timeline already mess up . what your guys expect for ?