Yeah, I edited my post after seeing you did the same thing.

My previous answer "yes" is for "conjunction が" in your pre-edited post.
I see, lol. How confusing. I'll get my post right the first time next time xD
Well I failed that.
だろう is "presumptive" who my opponent will be here, and "presumptive + が" gives a nuance of "even if".
Whoa...I see. Wow. Those words gave me a lot of deep insight actually, concerning "presumptive" and "will." Not just for Japanese, but for English as well. Reading and understanding this just gave me one of those clicking moments where you suddenly realize something. I feel I understand だろう a lot more now. Thank you for that.
は is for topicalization. In this case, the object/target 奴 is topicalized.
Okay, so I reasearched "topicalization" and see it is to do with the order in which things are said. I never knew it had a name. Interesting.
I have observed this in Japanese and became rather aware of it. I thought that it made sense. Sometimes subjectは is said first, sometimes it is after the sentence is "finished". It's like, order doesn't matter as long as you say everything and the correct particles are used. Generally it's SOV but with topicalization well, you know.
1. Does topicalization work like this:
知らない、私は or something which is then 私は知らない, but is the full thing not 私はそれを知らない or something. I recall something about using just は for emphasis with verbs, though.
2.Why does "奴は容赦しねェ!" mean "I won't give mercy to......"? There isn't an omitted form of 私 anywhere?
I feel I am missing something important or thinking about something incorrectly.
If I had known my question would branch out to something like this I would have made a seperate thread, again sorry.