So, I’ve wanted to know the answer to this for a while and I’ve hunted through the internet to find it, but literally no-where has any answers.
So, does anyone know what the ‘U’ on the back of Mercy’s pistol is? Like, I’m just so confused at why there’s a random U there on nearly all her skins.
It stands for ‘U will never know’
I’d say it’s not a U but the same design element she wears on her head.
This actually makes sense… But the “U will never know” sounds cooler 
On the inside of it there’s small printed text saying the word ‘no’
no u.
So its a no u blaster.
neat.
I always knew mercy was a memer.
It’s really apart of the Hemi-Halo theme she has like the one above her head. And because Mercy likes to Meme just consider some of her voice lines.
It stands for “un-heal”. You use it to un-heal enemies.
I like the “No U” theory 
I want it to be canon
You’re wrong.
It stands for “no U”, because you use it to kill those, who wanted to kill you… You can’t prove me wrong
Good luck horseshoe orientation?
“I’m gonna to kill you!” - a character
“No U” - Mercy
“… what?” - Character
gets destroyed by Mercy’s blaster
It’s the answer to the gretest overwatch question
Who is getting nerfed again?
Underpowered
Maybe the original, original design was for her pistol to be hitscan and she could hit the button there on her pistol to bring up the ironsights for a Call of Duty feel.
Either way it looks somehow connected to the ironsight-looking mechanism on top of her pistol.
Mercy: “Come here, Genji! My gun vill heal you for negative damage.”
It’s an energy pistol. If you watch closely, it dims as you fire.
For anyone wondering what OP is referring to
