He and Leviathan (the streamer one) used to do a podcast called Westmarch Workshop for D3 for years. Neinball is the one who is pretty into Lore so has spent time on not just that podcast, but as a guest on others since shortly after D3 came out. Very very nice guy IRL.
Holyknight is someone who is really into some of the art of the Diablo games and for around 10 years now has made wallpaper backgrounds and such. Here is a post he did with some D4 wallpapers and his links. I don’t think I have seen him on a stream or podcast before though (assuming it is the same person).