They both are about undercover narcotics cops and how they defeat crime syndicates while battling with their own devils ..... NSN hero fang mu and PN hero gan tianlei both are similar in terms of characters.... Also they both lose their fiance/wife and both their wife/fiance are upright .... More importantly they both are courageous and badass.... Also there is a good amount of whump and bromance in both ..... Also they both are very similar and patriotic so do try it if you like either one .... They both are so similar