Game making question

[YHWHVajrapani]

I plan to make my own DW and SW like game but wanbt to know what all keeps me from legal penalties copyrioght infringement. I know unless stated that certain officers may be KOEI make ups or exclusive you can't have this weapon on this character but what all is fair game for any game maker and what is copyright infringement?
have searched and asked many legal advice companies and continuous google searches for the copyrights to each Dynasty Warriors to find out what all is copyright patented and exclusive property of Koei and what anybody can doand have come up extremely empty! any advice is welcome.