re: 'was that Matt?', it's like Organization XIII all over again! Yeah, his part is only marginally bigger in the manga (he's in about fourteen panels, perhaps?). He has a tiny bit of backstory, I believe. Mostly that he's one of the orphanage kids as well, and he. likes video games. Of course that constitutes a backstory, sssh.

Soichiro, Matsuda, Aizawa and the other cops were my collective favourite characters in Death Note. That said, and in regards to what you mention about Near, I have a bit of a soft spot for Mello for the sorts of reasons you're mentioning. He's just refreshing in this series comprised so intensely around restrained and focused characters.