"Was unable to use" doesn't mean "didn't use", right? (originally 使わなかった訳じゃなくて、使わなかったんだよね。)

Hm?

So, about a little while ago... (originally それで、さっき見たら。。。)

This came into my hand by mistake. (originally 私の手持ちの中に、これが紛れていて)

This is...

...an empty spell card?

Don't you remember anything? (originally 何か覚えは無いのか？)

Originally it was a thing that you probably would have used fine, right? (originally 元々は使っていた物だろう？)

Yes...

I figured that, but... (originally その筈なんだけど)

...for some reason... (originally どういう訳か)

What was that spell card? I absolutely can't remember. これがどんなスペルカードだったか。。。どうしても思い出せないんだ。