I came across la guerre des 100 ans on youtube i think yesterday or was it nessy de london i dont remember but most titles were people's names
so i am asking myself whether its late def who introduced that spirit of "nayembeli mutu oyo" more than a title matching the story of the song(which he did have good stories btw unlike many current music)

Yeah, he already started it in 1995 when releasing the album Phily Mbala. Every song title having people's name. In 2000 there was a conflict because of a guy being mad that he paid for a song, but the song being dedicated to two people (I will not name the band), it created alot of polemic but in the coming years other bands would do the same thing due to a huge demand from people wanting to have a song. It was one of the reasons why artists started to release double albums, but the demand still being to high and some still dedicating one songs to two people. When Defao started recording Nessy de London he said that he would never give normal song titles anymore, just names to avoid those conflicts.