This card really tries to be good, but sorts of fails at it. To start: it's a 1/3 Construct (it's been errata'd) for 3. Power/toughness-wise, that's pretty "middle-of-the-road"; it's not as strong as Phyrexian Soulgorger but it's not as weak as Darksteel Myr (I'm only talking about power & toughness, not usefulness right now). But, how good is it for it's cost?
Well, it does kind of has firebreathing. It's colourless firebreathing, but it's also expensive firebreathing. However, it's pretty much expected that firebreathing will be more expensive if it's colourless (only Soldevi Simulacrum and Snow Fortress have cheaper firebeathing in the colourless world), so it can be forgiven for that. But... that's about this card's got going for it. Duskworker regenerates each time it gets blocked, meaning it's pretty useful if you throw a Lure on it. Steel Hellkite has an amazing ability on it, and say what you want about Roterothopter, at least it's got flying! All in all, it's not that great a card. Makes you think what the city of Kroog thought Mishra had. Rubber bands and a BB gun?
Pros: Standard colourless firebreathing, average power/toughness for cost
Cons: No evasion, pretty bland