I think it's an anime...

[Mercen-X]

The arrogant bastard roars: "Come at me. One at a time or all at once! It makes no difference." It's possible this is not verbatim.

The line is stuck in my head. I can't think of its origin and the search engines are being useless again. It even showed stuff for Once Upon a Time. I've tried multiple variations as I obsess over where I've heard this. I mostly turn up All At Once by Witchney Houston. Frock!

[Elite Lord Sigma]

I did a bit of searching for the exact quote on Google, and the only one I came up that sounds plausible is a quote by Sephiroth. From what game, I couldn't tell you. Then again, it came from a deviantART comments section, so make of that what you will.

[Mercen-X]

Although I still can't find anything on it, I'm starting to think something like this was said on Dragonball something-or-other.