Phoenix carries a Heavy Rocket Launcher, which fires two big templates worth of fire damage. Or three, when he is accompanied by a Myrmidon Fireteam. He's dumb, and I hate him.
The Black is of course based Black. Highlights are added with VMC 166 Dark Grey, 160 Neutral Grey, 155 Light Grey, and White.
The silver parts are painted with the same colors, but the highlights simply take up more surface area, resulting in a lighter color. Then they are glazed with a little bit of P3 Cygnar Highlight.