riddle - Piece de Resistance - Introduction & Ace and A's

OP's Words

_{This puzzle is part of the "Piece de Resistance" series. Read the following section for the story
Ace Two Three Four Five ...}

Hey guys (and gals), I have worked on this for weeks, took me even more effort than "A Masterpiece: A mirror or an ABC?". Hope y'all like it, and don't forget to press the upward button if you like it and/or appreciate my effort :D

Prologue

On Sunday night, you went to the bar to chill with your friend. After chatting for a while, your friend produced a deck of cards from his pocket.

"Here, happy birthday, mate! Bye for now!"

And then, without a word, he left.

You flipped through the cards, but they aren't the kind of playing cards you normally see. On the top-right corner of each of the cards are labels, from A through K. Strange though, there is no suit. You soon realised there is only one suit of 13 cards here.

Ace - and A's

You observed the Ace card in detail. It has a silver glossy surface. You tried rubbing a coin against the surface, and you realised there was another layer under the silver surface. The surface underneath was more like a typical playing card, with a white shiny facade. The black text on it says:

$\mathfrak{\text{Ace, I may be to the ear, without one letter.}}$
$\mathfrak{\text{A's, I may be to the eye, without two letters.}}$
$\mathfrak{\text{See? Three letters gone!}}$
$\mathfrak{\text{I am a victim.}}$

Answer

Case sounds like ace when you remove one letter (the first), looks like a's when you remove two letters (the first and last), is c (sounds like see) when you remove three letters (the last three), and is a victim of (falls to) arguments in a proof by cases. I don't, however, see a connection to the title ("Piece de Resistance - Introduction").