Mirko Filipovic and Anderson Silva. Cro Cop because I am Croatian and I remember family watching fights, my first memory being Nogueira armbar loss (I was 7 at the time, 2003). Then I already knew I like what I see.
Then it was playing UFC 2009 Undisputed game and enjoying the hell out of it, especially using Anderson and Chuck Lidell. So yeah those were all traces back from the childhood, it was always something. Consistent following started at around middle of 2010s up until now. Before it was just a bunch of popular fights only with the most famous guys and highlight videos. It was very enjoyable for me, but it was still not consistent as it was later.
But yeah, Cro Cop and Silva mythology was definitely strong for me all the way from the childhood.