I heard some call her “Small Package”.
 
Yes, very unoriginal, but they chose it due to the adage “Big things come in small packages.” So there.

@VermiIIion  
I call her Barb; as in barbed.  
She’s cute like a hedgehog, but give her strength she’s prickly to the touch in her own way just like a hedgehog.

We need more art.

We should name her Pygmy. Like a Pygmy Hedgehog? Fits better than Powerhouse.

@SeraphimDawn  
So would that make her “Mighty Shy”?

She’s got a Brienne of Tarth vibe. Not in size, perhaps, or uncouthness, but in embarrassed awkwardness at her own freakish, ungodly strenght.

I just want to hug her, but she’d probably break my back hugging me back.

@Dirty Bit  
It’s ALWAYS the quiet cute ones!

@SeraphimDawn
 
Also good. An excellent combination.

Who knew Western moe could actually be very good?

She also has Fluttershy’s eye design. Implying a quiet, soft, and maybe timid personality.

@bigdad  
After she throws the crystal from her biological mother from Equuypton into the North Pole.

@SeraphimDawn
 
Can you blame them? I enjoy those kinds of characters sometimes.

@DashingJack  
Trust me, man. It just doesn’t work in any serious context.

It’s official. MLP has gotten into making cute little anime girls with super strength.

@PumpJack  

 
I’m for this, but Latin pronunciation gets a bit tricky, and while “Erin O’ ––” is a good lead in, the last part “Keida/Keidae” is hard to form a pun with. The Irish words for “power” (cumhacht) and “purple” (corcra) still don’t work.
 
Celtic and Romance languages are hard to reconcile…
 
I’m also getting the urge to use an Incredibles pun as she’s blackmailed into not showing her strength, but can’t think of a good one.

@Tavelian  
That “Quyllis” can fly in the show’s narrative, and it doesn’t make sense for her to called “Powerhouse” so quickly, considering her super strength, at the time, was a secret.

@DashingJack  
Yes.
 
Because Macintosh is an apple.
 
…what’s your point.

@Tavelian  
As a nickname, yes. However, ponies do have names that are puns. Like Big Macintosh. Obviously, his name is just Macintosh, and the “Big” was added later when he got older.

@Dirty Bit  
nope… its pretty stupid

Awwwwwwwwww~. Powerhouse is a good name for her.

@Trahzo  
Oops, I meant…Then she kills Goku twice!

@bigdad  
Then she’s Goku twice!

@Shepherd  
Uh…I was actually thinking, since lunafan22 pointed out a similar color scheme, maybe she’s the ignored sibling.

ok when does she find a secret ice fortress at the north pole? XD