These may help you Amon, they seem to cover the basics:
www.law.cornell.edu/wex/index.php/Trademark
www.marklaw.com/trademark-glossary/T-Z.htm#Trademark%20Act
After scan reading quickly, it appears, that trademark dilution is only applicable where direct product competition (and on a large scale) is in effect. Otherwise the company must own the exact name you are using to trade under.
Which is exactly what I was getting at. I have of course assumed that your game is not a football game given the fighting title.
And no I am not a lawyer, didn't claim to be either.
What I and every single other person in this thread have done is post their own personal opinion, this may be based on experience of this side of the law, or knowledge from further education, in my case what I posted is based on both, I through a family member have experience with being taken to court for trademark infringement, and I also had course material at university that covered it although not in as much detail as a lawyers course would have.
Even tho I have experience in this matter, I still do not claim to be any sort of expert, and I stress again that anything I and anyone else above have said are only their opinions from their own experience.
There is an easy solution to your problem, and its a solution I took about 4 years ago when I registered a website for a small company that had ASDA in the domain name, I contacted ASDA, and let them know about the domain and what its contents were and asked if they had any problems with it, the answer of course was no, they didn't really care.